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Sample records for multistage ucn turbine

  1. Multi-stage internal gear/turbine fuel pump

    Energy Technology Data Exchange (ETDEWEB)

    Maier, Eugen; Raney, Michael Raymond

    2004-07-06

    A multi-stage internal gear/turbine fuel pump for a vehicle includes a housing having an inlet and an outlet and a motor disposed in the housing. The multi-stage internal gear/turbine fuel pump also includes a shaft extending axially and disposed in the housing. The multi-stage internal gear/turbine fuel pump further includes a plurality of pumping modules disposed axially along the shaft. One of the pumping modules is a turbine pumping module and another of the pumping modules is a gerotor pumping module for rotation by the motor to pump fuel from the inlet to the outlet.

  2. Advanced multistage turbine blade aerodynamics, performance, cooling, and heat transfer

    Energy Technology Data Exchange (ETDEWEB)

    Fleeter, S.; Lawless, P.B. [Purdue Univ., West Lafayette, IN (United States)

    1995-10-01

    The gas turbine has the potential for power production at the highest possible efficiency. The challenge is to ensure that gas turbines operate at the optimum efficiency so as to use the least fuel and produce minimum emissions. A key component to meeting this challenge is the turbine. Turbine performance, both aerodynamics and heat transfer, is one of the barrier advanced gas turbine development technologies. This is a result of the complex, highly three-dimensional and unsteady flow phenomena in the turbine. Improved turbine aerodynamic performance has been achieved with three-dimensional highly-loaded airfoil designs, accomplished utilizing Euler or Navier-Stokes Computational Fluid Dynamics (CFD) codes. These design codes consider steady flow through isolated blade rows. Thus they do not account for unsteady flow effects. However, unsteady flow effects have a significant impact on performance. Also, CFD codes predict the complete flow field. The experimental verification of these codes has traditionally been accomplished with point data - not corresponding plane field measurements. Thus, although advanced CFD predictions of the highly complex and three-dimensional turbine flow fields are available, corresponding data are not. To improve the design capability for high temperature turbines, a detailed understanding of the highly unsteady and three-dimensional flow through multi-stage turbines is necessary. Thus, unique data are required which quantify the unsteady three-dimensional flow through multi-stage turbine blade rows, including the effect of the film coolant flow. This requires experiments in appropriate research facilities in which complete flow field data, not only point measurements, are obtained and analyzed. Also, as design CFD codes do not account for unsteady flow effects, the next logical challenge and the current thrust in CFD code development is multiple-stage analyses that account for the interactions between neighboring blade rows.

  3. Optimization of organic Rankine cycle power systems considering multistage axial turbine design

    DEFF Research Database (Denmark)

    Meroni, Andrea; Andreasen, Jesper Graa; Persico, Giacomo

    2018-01-01

    Organic Rankine cycle power systems represent a viable and efficient solution for the exploitation of medium-to-low temperature heat sources. Despite the large number of commissioned units, there is limited literature on the design and optimization of organic Rankine cycle power systems considering...... multistage turbine design. This work presents a preliminary design methodology and working fluid selection for organic Rankine cycle units featuring multistage axial turbines. The method is then applied to the case of waste heat recovery from a large marine diesel engine. A multistage axial turbine model...

  4. Optimization of organic Rankine cycle power systems considering multistage axial turbine design

    DEFF Research Database (Denmark)

    Meroni, Andrea; Andreasen, Jesper Graa; Persico, Giacomo

    2017-01-01

    Organic Rankine cycle power systems represent a viable and efficient solution for the exploitation of medium-to-low temperature heat sources. Despite the large number of commissioned units, there is limited literature on the design and optimization of organic Rankine cycle power systems considering...... multistage turbine design. This work presents a preliminary design methodology and working fluid selection for organic Rankine cycle units featuring multistage axial turbines. The method is then applied to the case of waste heat recovery from a large marine diesel engine. A multistage axial turbine model...

  5. Aerodynamic Optimization Design of a Multistage Centrifugal Steam Turbine and Its Off-Design Performance Analysis

    OpenAIRE

    Hui Li; Dian-Gui Huang

    2017-01-01

    Centrifugal turbine which has less land occupation, simple structure, and high aerodynamic efficiency is suitable to be used as small to medium size steam turbines or waste heat recovery plant. In this paper, one-dimensional design of a multistage centrifugal steam turbine was performed by using in-house one-dimensional aerodynamic design program. In addition, three-dimensional numerical simulation was also performed in order to analyze design and off-design aerodynamic performance of the pro...

  6. UCN-VCN facility and experiments in Kyoto University Reactor

    International Nuclear Information System (INIS)

    Kawabata, Yuji; Okumura, Kiyoshi; Utsuro, Masahiko

    1993-01-01

    An ultracold and very cold neutron facility was installed in Kyoto University Reactor (KUR). The facility consists of a very cold neutron (VCN) guide tube, a VCN bender, a supermirror neutron turbine and experimental equipments with ultracold neutrons (UCN). The properties of each equipments are presented. UCN is generated by a supermirror neutron turbine combined with the cold neutron source operated with liquid deuterium, and the UCN output spectrum was measured by the time-of-flight method. A gravity analyzer for high resolution spectroscopy and a neutron bottle for decay experiments are now developing as the UCN research in KUR. (author)

  7. Aerodynamic Optimization Design of a Multistage Centrifugal Steam Turbine and Its Off-Design Performance Analysis

    Directory of Open Access Journals (Sweden)

    Hui Li

    2017-01-01

    Full Text Available Centrifugal turbine which has less land occupation, simple structure, and high aerodynamic efficiency is suitable to be used as small to medium size steam turbines or waste heat recovery plant. In this paper, one-dimensional design of a multistage centrifugal steam turbine was performed by using in-house one-dimensional aerodynamic design program. In addition, three-dimensional numerical simulation was also performed in order to analyze design and off-design aerodynamic performance of the proposed centrifugal steam turbine. The results exhibit reasonable flow field and smooth streamline; the aerodynamic performance of the designed turbine meets our initial expectations. These results indicate that the one-dimensional aerodynamic design program is reliable and effective. The off-design aerodynamic performance of centrifugal steam turbine was analyzed, and the results show that the mass flow increases with the decrease of the pressure ratio at a constant speed, until the critical mass flow is reached. The efficiency curve with the pressure ratio has an optimum efficiency point. And the pressure ratio of the optimum efficiency agrees well with that of the one-dimensional design. The shaft power decreases as the pressure ratio increases at a constant speed. Overall, the centrifugal turbine has a wide range and good off-design aerodynamic performance.

  8. Design and optimization of a multistage turbine for helium cooled reactor

    International Nuclear Information System (INIS)

    Braembussche, R.A. van den; Brouckaert, J.F.; Paniagua, G.; Briottet, L.

    2008-01-01

    This paper describes the aerodynamic design and explores the performance limits of a 600 MWt multistage helium turbine for a high temperature nuclear reactor closed cycle gas turbine. The design aims for maximum performance while limiting the number of stages for reasons of rotor dynamics and weight. A first part discusses the arguments that allow a preliminary selection of the overall dimensions by means of performance prediction correlations and simplified stress considerations. The rotational speed being fixed at 3000 rpm, the only degrees of freedom for the design are: the impeller diameter, number of stages and stage loading. The optimum load distribution of the different stages, the main flow parameters and the blade overall dimensions are defined by means of a 2D through-flow analysis method. The resulting absolute and relative flow angles and span-wise velocity variation are the input for a first detailed design by an inverse method. The latter defines the different 2D blade sections corresponding to prescribed optimum velocity distributions. The final 3D blade definition is made by means of a computer based 3D-DESIGN system developed at the von Karman Institute. This method combines a 3D Navier-Stokes (NS) solver, Database, Artificial Neural Network and Genetic Algorithm into a two level optimization technique for compressor and turbine stages. The use of 3D Navier-Stokes solvers allows full accounting of the secondary flow losses and optimization of the compound leaning of the stator vanes. The performance of the individual stages is used to define the multistage operating curves. The last part of the paper describes an evaluation of the cooling requirements of the first turbine rotor

  9. Analysis of experimental characteristics of multistage steam-jet electors of steam turbines

    Science.gov (United States)

    Aronson, K. E.; Ryabchikov, A. Yu.; Brodov, Yu. M.; Brezgin, D. V.; Zhelonkin, N. V.; Murmanskii, I. B.

    2017-02-01

    A series of questions for specification of physical gas dynamics model in flow range of steam-jet unit and ejector computation methodology, as well as functioning peculiarities of intercoolers, was formulated based on analysis of experimental characteristics of multistage team-jet steam turbines. It was established that coefficient defining position of critical cross-section of injected flow depends on characteristics of the "sound tube" zone. Speed of injected flow within this tube may exceed that of sound, and pressure jumps in work-steam decrease at the same time. Characteristics of the "sound tube" define optimal axial sizes of the ejector. According to measurement results, the part of steam condensing in the first-stage coolant constitutes 70-80% of steam amount supplied into coolant and is almost independent of air content in steam. Coolant efficiency depends on steam pressure defined by operation of steam-jet unit of ejector of the next stage after coolant of steam-jet stage, temperature, and condensing water flow. As a rule, steam entering content of steam-air mixture supplied to coolant is overheated with respect to saturation temperature of steam in the mixture. This should be taken into account during coolant computation. Long-term operation causes changes in roughness of walls of the ejector's mixing chamber. The influence of change of wall roughness on ejector characteristic is similar to the influence of reverse pressure of the steam-jet stage. Until some roughness value, injection coefficient of the ejector stage operating in superlimiting regime hardly changed. After reaching critical roughness, the ejector switches to prelimiting operating regime.

  10. On the superthermal UCN production

    International Nuclear Information System (INIS)

    Yoshiki, Hajime

    1996-01-01

    In 1992, the production of ultracold neutrons (UCN) by means of superthermal method predicted by Golub and Pendlebury was verified quantitatively by changing incident cold neutron wavelength to observe the maximum of UCN production at a certain wavelength. At this wavelength, the dispersion curve of superfluid liquid helium and the energy momentum curve of a free neutron cross, and the energy and momentum of incident neutrons can be converted entirely to those of produced phonons, thus the neutrons with infinitesimal energy are left, which are UCN. It was learned that the calculation by Cohen and Feynman is correct, and now the rate of UCN production per unit time can be calculated. The comparison of this with other methods is discussed. The heat that would be produced in liquid helium if it was exposed to a cold neutron field was calculated. The proposed set of the circulation pumps for 3 He combined with a new heat exchanger gives the answer to the problem. Two main objectives for getting a strong UCN source are the precise determination of neutron lifetime and the search for the electric dipole moment of neutrons. The e.d.m. measurement machine integrated with refrigeration parts is shown. Preliminary measurement was done for the three-layer high permeability shield. (K.I.)

  11. On the superthermal UCN production

    Energy Technology Data Exchange (ETDEWEB)

    Yoshiki, Hajime [National Lab. for High Energy Physics, Tsukuba, Ibaraki (Japan)

    1996-08-01

    In 1992, the production of ultracold neutrons (UCN) by means of superthermal method predicted by Golub and Pendlebury was verified quantitatively by changing incident cold neutron wavelength to observe the maximum of UCN production at a certain wavelength. At this wavelength, the dispersion curve of superfluid liquid helium and the energy momentum curve of a free neutron cross, and the energy and momentum of incident neutrons can be converted entirely to those of produced phonons, thus the neutrons with infinitesimal energy are left, which are UCN. It was learned that the calculation by Cohen and Feynman is correct, and now the rate of UCN production per unit time can be calculated. The comparison of this with other methods is discussed. The heat that would be produced in liquid helium if it was exposed to a cold neutron field was calculated. The proposed set of the circulation pumps for {sup 3}He combined with a new heat exchanger gives the answer to the problem. Two main objectives for getting a strong UCN source are the precise determination of neutron lifetime and the search for the electric dipole moment of neutrons. The e.d.m. measurement machine integrated with refrigeration parts is shown. Preliminary measurement was done for the three-layer high permeability shield. (K.I.)

  12. UCN anomalous losses and the UCN capture cross section on material defects

    International Nuclear Information System (INIS)

    Serebrov, A.; Romanenko, N.; Zherebtsov, O.; Lasakov, M.; Vasiliev, A.; Fomin, A.; Geltenbort, P.; Krasnoshekova, I.; Kharitonov, A.; Varlamov, V.

    2005-01-01

    Experimental data shows anomalously large ultra cold neutrons (UCN) reflection losses and that the process of UCN reflection is not completely coherent. UCN anomalous losses under reflection cannot be explained in the context of neutron optics calculations. UCN losses by means of incoherent scattering on material defects are considered and cross-section values calculated. The UCN capture cross section on material defects is enhanced by a factor of 10 4 due to localization of UCN around defects. This phenomenon can explain anomalous losses of UCN

  13. A large area silicon UCN detector with the analysis of UCN polarization

    International Nuclear Information System (INIS)

    Lasakov, M.S.; Serebrov, A.P.; Khusainov, A.Kh.; Pustovoit, A.; Borisov, Yu.V.; Fomin, A.K.; Geltenbort, P.; Kon'kov, O.I.; Kotina, I.M.; Shablii, A.I.; Solovei, V.A.; Vasiliev, A.V.

    2005-01-01

    A silicon UCN detector with an area of 45cm 2 and with a 6 LiF converter was developed at PNPI. The spectral efficiency of the silicon UCN detector was measured by means of a gravitational spectrometer at ILL. The sandwich-type detector from two silicon plates with a 6 LiF converter placed between them was also studied. Using this type of technology the UCN detector with analysis of polarization was developed and tested. The analyzing power of this detector assembly reaches up to 75% for the main part of UCN spectrum. This UCN detector with analysis of UCN polarization can be used in the new EDM spectrometer

  14. Recent UCN source developments at Los Alamos

    International Nuclear Information System (INIS)

    Seestrom, S.J.; Anaya, J.M.; Bowles, T.J.

    1998-01-01

    The most intense sources of ultra cold neutrons (UCN) have bee built at reactors where the high average thermal neutron flux can overcome the low UCN production rate to achieve usable densities of UCN. At spallation neutron sources the average flux available is much lower than at a reactor, though the peak flux can be comparable or higher. The authors have built a UCN source that attempts to take advantage of the high peak flux available at the short pulse spallation neutron source at the Los Alamos Neutron Science Center (LANSCE) to generate a useful number of UCN. In the source UCN are produced by Doppler-shifted Bragg scattering of neutrons to convert 400-m/s neutrons down into the UCN regime. This source was initially tested in 1996 and various improvements were made based on the results of the 1996 running. These improvements were implemented and tested in 1997. In sections 2 and 3 they discuss the improvements that have been made and the resulting source performance. Recently an even more interesting concept was put forward by Serebrov et al. This involves combining a solid Deuterium UCN source, previously studied by Serebrov et al., with a pulsed spallation source to achieve world record UCN densities. They have initiated a program of calculations and measurements aimed at verifying the solid Deuterium UCN source concept. The approach has been to develop an analytical capability, combine with Monte Carlo calculations of neutron production, and perform benchmark experiments to verify the validity of the calculations. Based on the calculations and measurements they plan to test a modified version of the Serebrov UCN factory. They estimate that they could produce over 1,000 UCN/cc in a 15 liter volume, using 1 microamp of 800 MeV protons for two seconds every 500 seconds. They will discuss the result UCN production measurements in section 4

  15. Analisis Performansi Pompa Multistage Pengisi Air Umpan Ketel Yang Digerakkan Oleh Turbin Uap Dibanding Dengan Elektromotor

    OpenAIRE

    Nasution, Asril Habibi

    2012-01-01

    The pump is a fluid machinery that serves to move the fluid from the fluid incompressible / low pressure to the place / higher pressure. In principle, the pump convert mechanical energy into fluid energy. Centrifugal pump is included into the type of dynamic pressure pumps, which pump impeller type has a function to remove fluid from a low place to place a higher or lower than the pressure to higher pressure. In this analysis the pump used is a multistage centrifugal pump is driven by the ste...

  16. Evaluation of advanced turbomachinery for underground pumped hydroelectric storage. Part 3. Multistage unregulated pump/turbines for operating heads of 1000 to 1500 m

    Energy Technology Data Exchange (ETDEWEB)

    Frigo, A.A.; Pistner, C.

    1980-08-01

    This is the final report in a series of three on studies of advanced hydraulic turbomachinery for underground pumped hydroelectric storage. All three reports address Francis-type, reversible pump/turbines. The first report covered single-stage regulated units; the second report covered two-stage regulated units; the present report covers multistage unregulated units. Multistage unregulated pump/turbines offer an economically attractive option for heads of 1000 to 1500 m. The feasibility of developing such machines for capacities up to 500 MW and operating heads up to 1500 m has been evaluated. Preliminary designs have been generated for six multistage pump/turbines. The designs are for nominal capacities of 350 and 500 MW and for operating heads of 1000, 1250, and 1500 m. Mechanical, hydraulic, and economic analyses indicate that these machines will behave according to the criteria used to design them and that they can be built at a reasonable cost with no unsolvable problems. Efficiencies of 85.8% and 88.5% in the generating and pumping modes, respectively, can be expected for the 500-MW, 1500-m unit. Performances of the other five machines are at least comparable, and usually better. Over a 1000 to 1500-m head range, specific $/kW costs of the pump/turbines in mid-1978 US dollars vary from 19.0 to 23.1 for the 500-MW machines, and from 21.0 to 24.1 for the 350-MW machines.

  17. Stall/surge dynamics of a multi-stage air compressor in response to a load transient of a hybrid solid oxide fuel cell-gas turbine system

    Science.gov (United States)

    Azizi, Mohammad Ali; Brouwer, Jacob

    2017-10-01

    A better understanding of turbulent unsteady flows in gas turbine systems is necessary to design and control compressors for hybrid fuel cell-gas turbine systems. Compressor stall/surge analysis for a 4 MW hybrid solid oxide fuel cell-gas turbine system for locomotive applications is performed based upon a 1.7 MW multi-stage air compressor. Control strategies are applied to prevent operation of the hybrid SOFC-GT beyond the stall/surge lines of the compressor. Computational fluid dynamics tools are used to simulate the flow distribution and instabilities near the stall/surge line. The results show that a 1.7 MW system compressor like that of a Kawasaki gas turbine is an appropriate choice among the industrial compressors to be used in a 4 MW locomotive SOFC-GT with topping cycle design. The multi-stage radial design of the compressor enhances the ability of the compressor to maintain air flow rate during transient step-load changes. These transient step-load changes are exhibited in many potential applications for SOFC/GT systems. The compressor provides sustained air flow rate during the mild stall/surge event that occurs due to the transient step-load change that is applied, indicating that this type of compressor is well-suited for this hybrid application.

  18. Quasi-elastic spectral change of stored UCN

    International Nuclear Information System (INIS)

    Geltenbort, P.; Butterworth, J.; Steyerl, A.; Kwon, O.; Yerozolimsky, B.; Achiwa, N.

    2001-01-01

    UCN within a narrow spectral range were stored in a Fomblin grease coated trap. After filling the trap the bandwidth of storable UCN could be reduced to zero by an absorber. This procedure did, however, not remove all UCN. As in our previous measurements, the remaining UCN were found to leave the trap with an efflux time constant significantly larger than the value measured for the initial UCN spectrum. The remaining fraction of UCN was reduced to zero only when the absorber was brought down almost to the bottom of the trap. The data can be explained, qualitatively, by quasi-elastic UCN down-scattering by about 4 neV during the filling process. The deduced probability for this process is compared to a calculation for a model of hydrogen diffusing within a thin hydrogenous layer on top of the Fomblin grease. (author)

  19. An ultracold neutron storage bottle for UCN density measurements

    Energy Technology Data Exchange (ETDEWEB)

    Bison, G.; Burri, F.; Daum, M. [Paul Scherrer Institute (PSI), CH-5232 Villigen PSI (Switzerland); Kirch, K. [Paul Scherrer Institute (PSI), CH-5232 Villigen PSI (Switzerland); Institute for Particle Physics, Eidgenössische Technische Hochschule (ETH), Zürich (Switzerland); Krempel, J. [Institute for Particle Physics, Eidgenössische Technische Hochschule (ETH), Zürich (Switzerland); Lauss, B., E-mail: bernhard.lauss@psi.ch [Paul Scherrer Institute (PSI), CH-5232 Villigen PSI (Switzerland); Meier, M. [Paul Scherrer Institute (PSI), CH-5232 Villigen PSI (Switzerland); Ries, D., E-mail: dieter.ries@psi.ch [Paul Scherrer Institute (PSI), CH-5232 Villigen PSI (Switzerland); Institute for Particle Physics, Eidgenössische Technische Hochschule (ETH), Zürich (Switzerland); Schmidt-Wellenburg, P.; Zsigmond, G. [Paul Scherrer Institute (PSI), CH-5232 Villigen PSI (Switzerland)

    2016-09-11

    We have developed a storage bottle for ultracold neutrons (UCNs) in order to measure the UCN density at the beamports of the Paul Scherrer Institute's (PSI) UCN source. This paper describes the design, construction and commissioning of the robust and mobile storage bottle with a volume comparable to typical storage experiments (32 L) e.g. searching for an electric dipole moment of the neutron.

  20. Time-of-flight Fourier spectrometry of UCN

    International Nuclear Information System (INIS)

    Kulin, G.V.; Frank, A.I.; Goryunov, S.V.; Kustov, D.V.; Geltenbort, P.; Jentshel, M.; Strepetov, A.N.; Bushuev, V.A.

    2014-01-01

    The results of preliminary experiments on TOF Fourier UCN spectrometry are presented. The description of the new Fourier spectrometer that may be used for the measurement of the UCN spectra arising from diffraction by a moving grating is given. The results of preliminary experiments and Monte Carlo calculations give reason to hope for the success of the planned experiment.

  1. Performance Evaluation of the Multi-stage Tower-type Vertical-axis Wind Turbine%多层塔式H型立轴风机的性能分析

    Institute of Scientific and Technical Information of China (English)

    高振勋; 蒋崇文; 唐金龙; 王德宝

    2011-01-01

    The main ideal of the multi-stage tower type vertical-axis wind turbine is to utilize the superposition of multi group H-type vertical-axis wind turbines to generate power, and fully use the wind energy in different altitude, which is beneficial for the large-scale development of modern wind turbine. The performance compari sons between the multi-stage tower-type vertical-axis wind turbine and traditional wind turbine were performed on many aspects. It was pointed out that the multi-stage tower-type vertical-axis wind turbine can have many advantages, such as easy-machining blades, high power efficiency, avoidance of the yawing system, reasonable structure loading, and low manufacture/maintenance cost. However, some disadvantages exist, such as the aerodynamic drag brought in by the blade supporting structure, complicated tower construction, and incremental requirement for gearbox and shaft joint. Overall considering, the multi stage tower-type vertical-axis wind turbine has extensive prospect of market applications.%多层塔式立轴风机的核心思想是将多组H型立轴风机分层叠加组合发电,结构简单性能优异,非常适合大容量的风电机组,符合现代风机向大型化发展的方向。对多层塔式立轴风机与传统风机的多方面性能进行了对比,指出多层塔式立轴风机具有风能利用率高、叶片制造简单、无需偏航系统、结构载荷合理、制造维护成本低等诸多优点,但也存在一些缺点,如叶片支撑结构会引入气动阻力、塔架设计较复杂、需要多组齿轮箱及联轴器等。总体分析表明,多层塔式立轴风机的方案在技术上和经济上是可行的。

  2. Concepts of UCN sources for the FRM-II

    CERN Document Server

    Trinks, U; Paul, S; Schott, W

    2000-01-01

    Three concepts for sources of ultra-cold neutrons (UCN) for the reactor FRM-II at Garching near Munich are studied: one, Mini-D sub 2 , is a source with 170 cm sup 3 of solid deuterium in the beam tube SR4 and the second one a large solid-deuterium source (volume about 30 dm sup 3), mounted in the beam tube SR5 as an advanced cold source with a number of neutron guides. The third one, Mark 3000, uses superfluid sup 4 He at a cold-neutron guide. A UCN density of up to 7x10 sup 4 cm sup - sup 3 may possibly be achieved in the storage volumes of Mini-D sub 2 yielding more than 10 sup 9 UCN for extraction to an attached experimental setup. The usable UCN flux at the periphery of the large deuterium source is predicted to be 2x10 sup 7 cm sup - sup 2 s sup - sup 1. Mark 3000, finally, is expected to yield a UCN density of about 10 sup 5 cm sup - sup 3.

  3. A Superconducting Magnet UCN Trap for Precise Neutron Lifetime Measurements.

    Science.gov (United States)

    Picker, R; Altarev, I; Bröcker, J; Gutsmiedl, E; Hartmann, J; Müller, A; Paul, S; Schott, W; Trinks, U; Zimmer, O

    2005-01-01

    Finite-element methods along with Monte Carlo simulations were used to design a magnetic storage device for ultracold neutrons (UCN) to measure their lifetime. A setup was determined which should make it possible to confine UCN with negligible losses and detect the protons emerging from β-decay with high efficiency: stacked superconducting solenoids create the magnetic storage field, an electrostatic extraction field inside the storage volume assures high proton collection efficiency. Alongside with the optimization of the magnetic and electrostatic design, the properties of the trap were investigated through extensive Monte Carlo simulation.

  4. Monte Carlo Modeling the UCN τ Magneto-Gravitational Trap

    Science.gov (United States)

    Holley, A. T.; UCNτ Collaboration

    2016-09-01

    The current uncertainty in our knowledge of the free neutron lifetime is dominated by the nearly 4 σ discrepancy between complementary ``beam'' and ``bottle'' measurement techniques. An incomplete assessment of systematic effects is the most likely explanation for this difference and must be addressed in order to realize the potential of both approaches. The UCN τ collaboration has constructed a large-volume magneto-gravitational trap that eliminates the material interactions which complicated the interpretation of previous bottle experiments. This is accomplished using permanent NdFeB magnets in a bowl-shaped Halbach array to confine polarized UCN from the sides and below and the earth's gravitational field to trap them from above. New in situ detectors that count surviving UCN provide a means of empirically assessing residual systematic effects. The interpretation of that data, and its implication for experimental configurations with enhanced precision, can be bolstered by Monte Carlo models of the current experiment which provide the capability for stable tracking of trapped UCN and detailed modeling of their polarization. Work to develop such models and their comparison with data acquired during our first extensive set of systematics studies will be discussed.

  5. Measurement of Systematic effects in the UCN τ neutron lifetime experiment

    Science.gov (United States)

    Callahan, Nathan; UCNtau Collaboration

    2017-09-01

    The UCN τ experiment at the Los Alamos Neutron Science Center (LANSCe) measures the neutron β decay lifetime (τn) by trapping Ultracold Neutrons (UCN) in a magneto-gravitational trap. UCN are confined from below by magnetic fields and above by gravity. UCN are loaded into the trap, held for times on the order of τn, and counted. Several systematic effects can potentially shift the measured τn including heating and other losses of UCN during storage, insufficient removal of UCN with energies above the traping potential, and phase space evolution of UCN during storage which can cause changes in detection efficiency. The UCN τ collaboration has put limits on these systematic effects via measurements in the 2016-2017 run cycle at LANSCE. For the first two effects, a limit is placed by searching for high-energy UCN at the end of storage. A limit is placed on the effects of phase space evolution by comparing arrival time distributions for UCN under different conditions. Data from the 2016-2017 run cycle and systematic limits derived from it will be discussed.

  6. AG Turbo, Turbotech 2. Subproject 1.422: Endwall effects in a multistage low pressure turbine rig. Final report; AG Turbo, Turbotech 2. Teilvorhaben 1.422: Seitenwandeffekte im mehrstufigen Niederdruck-Turbinenrig. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Eymann, S.

    2001-07-01

    Reducing the secondary losses in the bladed annulus of compressors and turbines is one approach to enhance the efficiency of turbo components of modern gas turbines. The aim of this project is to analyse the influence of endwall contouring and 3D airfoil design in the endwall region on the generation of secondary flows in a multistage low pressure turbine. Therefore experimental studies were carried out in a three stage cold flow test rig. First in a reference blading the flow fields in the axial gapes between the rows were conducted with pneumatic probes and with a 3D-L2F system (DLR Koeln) and with 3D hot wire probes (RWTH Aachen) by the project partners. Pressure distributions on several stram line positions and endwall pressure measuring points are employed to assess the vane flow. In a second phase the inlet guide vanes and the blades of the first rotor were replaced with a blading with endwall contouring and modified airfoilds in the endwall region, which was designed by the project partner MTU. The investigations were carried out in the same manner as before. In comparison to the results of the reference blading the secondary losses in the plane downstream the optimised inlet guide van could be reduced about 20% in the outer region. A reduction in the secondary flow phenomen, the passage vortex, can be traced back to reduced cross channel pressure gradients at the endwall. The secondary losses in the tip region could be moved closer to the casing. After the following rows downstream the optimised first turbine stage there was no positive influence on the development of secondary flows detectable. A data base was generated to validate and to improve current numerical methods. The physical understanding of secondary flows in multistage turbines was deepened. (orig.) [German] Ein Ansatz zur weiteren Steigerung des Wirkungsgrades in den Turbokomponenten moderner Gasturbinen ist die Reduzierung der durch Sekundaerstroemungen verursachten Verluste im beschaufelten

  7. A user facilitated autonomous load balancing framework for UCN

    OpenAIRE

    Yildiz, Mürsel

    2013-01-01

    Neben dem klassischen, providerzentrierten Konzept eines zentralen Internet-Anbieters und Benutzern als Internetkonsumenten, verspricht das Konzept des User Centric Networking (UCN) ein alternativen Lösungsansatz. Dieses Konzept ist attraktiv für Internetanbieter sowie für Endnutzer, da Endnutzer, als Internet-Stakeholder, sowohl Mikro-Netzbetreiber als auch Nutzer des Inhalts sind [1]. Der IEEE 802.11-Standard stellt aufgrund seiner weltweiten Verfügbarkeit, Effizienz und Kosteneffizienz ein...

  8. In-Pile 4He Source for UCN Production at the ESS

    International Nuclear Information System (INIS)

    Zanini, Luca; Batkov, Konstantin; Takibayev, Alan; Mezei, Ferenc; Klinkby, Esben; Schönfeldt, Troels; Pitcher, Eric

    2014-01-01

    ESS will be a premier neutron source facility. Unprecedented neutron beam intensities are ensured by spallation reactions of a 5 MW, 2.0 GeV proton beam impinging on a tungsten target equipped with advanced moderators. The work presented here aims at investigating possibilities for installing an ultra cold neutron (UCN) source at the ESS. One consequence of using the recently proposed flat moderators is that they take up less space than the moderators originally foreseen and thus leave more freedom to design a UCN source, close to the spallation hotspot. One of the options studied is to place a large 4 He UCN source in a through-going tube which penetrates the shielding below the target. First calculations of neutron flux available for UCN production are given, along with heat-load estimates. It is estimated that the flux can give rise to a UCN production at a rate of up to 1.5·10 8 UCN/s. A production in this range potentially allows for a number of UCN experiments to be carried out at unprecedented precision, including, for example, quantum gravitational spectroscopy with UCNs which rely on high phase-space density

  9. UCN storage experiment for the investigation of the anomalous interaction with wall surfaces

    International Nuclear Information System (INIS)

    Kawabata, Yuji; Utsuro, Masahiko; Steyerl, A.; Malik, S.S.; Geltenbort, P.; Neumair, S.; Nesvizhevsky, V.V.

    1997-01-01

    The UCN experiment for the investigation of the anomalous interaction with wall surfaces was performed in the ILL UCN source. UCN is monochromated by the gravity and stored in the spectrometer with rectangular trap which is the Fombrin-grease coated box of 67x67cm 2 cross section and 20cm height. The measured energy distribution of stored UCN shows the indication of 'initial micro-heating'. The order of energy gain is ∼ 10 -10 eV in the initial several 100sec of storage. (author)

  10. UCN gravity spectrometry using neutron interference filters for fundamental investigations in neutron optics

    CERN Document Server

    Bondarenko, I V; Cimmino, A; Geltenbort, P; Frank, A I; Hoghoj, P; Klein, A G; Masalovich, S V; Nosov, V G

    2000-01-01

    A Gravity Spectrometer for ultra-cold neutrons (UCN) using neutron interference filters has been designed and tested. An energy resolution of the order of 6.5 neV was obtained which is good enough for performing a number of neutron-optical experiments proposed in an earlier paper. Experimental tests of the UCN dispersion law are currently in progress.

  11. Review of inelastic losses of UCN and quantum mechanics of the de Broglie wave packet

    International Nuclear Information System (INIS)

    Ignatovich, V.K.; Utsuro, M.

    1998-01-01

    Different inelastic processes of ultracold neutrons (UCN) losses in traps are considered. A hypothesis of the de Broglie singular wave-packet description of the neutron wave-function to explain anomalous losses of UCN is proposed. An experiment to check the hypothesis and its results are discussed

  12. UCN gravity spectrometry using neutron interference filters for fundamental investigations in neutron optics

    International Nuclear Information System (INIS)

    Bondarenko, I.V.; Balashov, S.N.; Cimmino, A.; Geltenbort, P.; Frank, A.I.; Hoghoj, P.; Klein, A.G.; Masalovich, S.V.; Nosov, V.G.

    2000-01-01

    A Gravity Spectrometer for ultra-cold neutrons (UCN) using neutron interference filters has been designed and tested. An energy resolution of the order of 6.5 neV was obtained which is good enough for performing a number of neutron-optical experiments proposed in an earlier paper. Experimental tests of the UCN dispersion law are currently in progress

  13. UCN sources at external beams of thermal neutrons. An example of PIK reactor

    International Nuclear Information System (INIS)

    Lychagin, E.V.; Mityukhlyaev, V.A.; Muzychka, A.Yu.; Nekhaev, G.V.; Nesvizhevsky, V.V.; Onegin, M.S.; Sharapov, E.I.; Strelkov, A.V.

    2016-01-01

    We consider ultracold neutron (UCN) sources based on a new method of UCN production in superfluid helium ("4He). The PIK reactor is chosen as a perspective example of application of this idea, which consists of installing "4He UCN source in the beam of thermal or cold neutrons and surrounding the source with moderator-reflector, which plays the role of cold neutron (CN) source feeding the UCN source. CN flux in the source can be several times larger than the incident flux, due to multiple neutron reflections from the moderator–reflector. We show that such a source at the PIK reactor would provide an order of magnitude larger density and production rate than an analogous source at the ILL reactor. We estimate parameters of "4He source with solid methane (CH_4) or/and liquid deuterium (D_2) moderator–reflector. We show that such a source with CH_4 moderator–reflector at the PIK reactor would provide the UCN density of ~1·10"5 cm"−"3, and the UCN production rate of ~2·10"7 s"−"1. These values are respectively 1000 and 20 times larger than those for the most intense UCN user source. The UCN density in a source with D_2 moderator-reflector would reach the value of ~2·10"5 cm"−"3, and the UCN production rate would be equal ~8·10"7 s"−"1. Installation of such a source in a beam of CNs would slightly increase the density and production rate.

  14. Solid deuterium and UCN factory: application to the neutron electric dipole moment measurement

    CERN Document Server

    Serebrov, A P

    2000-01-01

    Present experiments which search for an electric dipole moment (EDM) of the neutron use ultra-cold neutrons (UCN) and are limited by counting statistics. One way to solve this problem is to improve the source of UCN. The present article briefly reviews two possibilities which employ solid deuterium at the temperature of liquid helium. The possibility of installing a solid deuterium UCN source at the FRM-II reactor and at spallation neutron sources at PSI, LANL and KEK is discussed. An increase of the UCN density up to the level of 10 sup 3 -10 sup 4 cm sup - sup 3 is expected. Compared to existing sources, this corresponds to an improvement by two to three orders of magnitude. Such experimental facilities will make it possible to improve measurements of the EDM of the neutron down to the level of 10 sup - sup 2 sup 7 e cm.

  15. Evaluation of load rejection to house load test at 50% power for UCN 3

    International Nuclear Information System (INIS)

    Lee, Chang Gyun; Sohn, Suk Whun; Sohn, Jong Joo; Seo, Jong Tae; Lee, Sang Keun; Kim, Yong Sung; Nam, Kyu Won; Jung, Yang Mook; Chae, Kyeong Sik; Koh, Bum Jae; Oh, Chul Sung; Park, Hee Chool

    1998-01-01

    The Load Rejection to House Load test at 50% power was successfully performed during the UCN 3 PAT period. In this test, all plant control systems automatically controlled the plant from 50% power to house load operation mode. The KISPAC code, which was used in the performance analysis during the design process of UCN 3 and 4, predictions of the test agreed with the measured data demonstrating the validity of the code as well as completeness of the plant design

  16. Setup for precise measurement of neutro lifetime by UCN storage method with inelastically scattered neutron detection

    International Nuclear Information System (INIS)

    Arzumanov, S.S; Bondarenko, L.N.; Gel'tenbort, P.; Morozov, V.I.; Nesvizhevskij, V.V.; Panin, Yu.N.; Strepetov, A.N.

    2007-01-01

    The experimental setup and the method of measuring the neutron lifetime with a precision less then 1 s is described. The measurements will be carried out by storage of ultracold neutrons (UCN) into vessels with inner walls coated with fluorine polymer oil with simultaneous registration of inelastically scattered UCN leaving storage vessels. The analysis of statistical and methodical errors is carried out. The calculated estimation of the measurement accuracy is presented [ru

  17. An experiment on the investigation of the possibilities of the detection of heated UCN at the IBR-2

    International Nuclear Information System (INIS)

    Kalchev, S.D.; Strelkov, A.V.

    1990-01-01

    An experiment on the investigation of the heating of ultracold neutrons (UCN) in the reactor IBR-2 is described. By measuring the flux of thermal neutrons (upscattered UCN heated on polyethylene) the UCN flux density in a neutron guide is estimated to be approx. 25 cm -2 s -1 . The paper reports on the analysis of the background of a counter of heated neutrons. 9 refs.; 5 figs

  18. Experiment on search for neutron-antineutron oscillations using a projected UCN source at the WWR-M reactor

    Science.gov (United States)

    Fomin, A. K.; Serebrov, A. P.; Zherebtsov, O. M.; Leonova, E. N.; Chaikovskii, M. E.

    2017-01-01

    We propose an experiment on search for neutron-antineutron oscillations based on the storage of ultracold neutrons (UCN) in a material trap. The sensitivity of the experiment mostly depends on the trap size and the amount of UCN in it. In Petersburg Nuclear Physics Institute (PNPI) a high-intensity UCN source is projected at the WWR-M reactor, which must provide UCN density 2-3 orders of magnitude higher than existing sources. The results of simulations of the designed experimental scheme show that the sensitivity can be increased by ˜ 10-40 times compared to sensitivity of previous experiment depending on the model of neutron reflection from walls.

  19. Resonant tunneling of UCN through the moving interference filter and experimental test of the UCN dispersion law

    International Nuclear Information System (INIS)

    Frank, A.I.; Bondarenko, I.V.; Balashov, S.N.; Geltenbort, P.; Hoghoj, P.; Kozlov, A.V.; Masalovich, S.V.; Toperverg, B.P.

    2004-01-01

    With the aim to test experimentally the dispersion law validity for very slow neutrons a spectrum of ultracold neutrons (UCN) under the condition of resonance tunneling through the moving Neutron Interference Filter was investigated. The neutron spectrum in this case has a narrow width resonance, whose parameters depend on the filter characteristics and dispersion law of neutron waves in matter. For a number of samples a noticeable shift of the resonance position when the filter moved parallel to its surface was detected. This shift is in strong contradiction with the commonly accepted dispersion law. Further investigations have shown that the spectrum of tunneling neutrons is not exactly defined by the solution of one-dimensional quantum problem, but substantially affected by neutron scattering from filter imperfections. The cross section of this scattering depends on the neutron wave number and increases dramatically in resonance conditions. Experimental results as well as comprehensive theoretical analysis have led us to the unambiguous conclusion that observed phenomena of the resonance shift in a moving sample are caused by scattering of neutron tunneling states rather than by a deviation from the commonly accepted dispersion law. (author)

  20. Evaluation of Load Rejection to house load test at 50% power for UCN 3

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chang Gyun; Sohn, Suk Whun; Sohn, Jong Joo; Seo, Jong Tae; Lee, Sang Keun [Korea Power Engineering Company, Inc., Seoul (Korea, Republic of); Kim, Yong Sung; Nam, Kyu Won; Jung, Yang Mook; Chae, Kyeong Sik; Koh, Bum Jae; Oh, Chul Sung; Park, Hee Chool [Korea Electric Power Corporation, Taejon (Korea, Republic of)

    1999-12-31

    The Load Rejection to House Load test at 50% power was successfully performed during the UCN 3 PAT period. In this test, all plant control systems automatically controlled the plant from 50% power to house load operation mode. The KISPAC code, which was used in the performance analysis during the design process of UCN 3 and 4, predictions of the test agreed with the measured data demonstrating the validity of the code as well as the completeness of the plant design. 3 refs., 8 figs., 1 tab. (Author)

  1. Evaluation of Load Rejection to house load test at 50% power for UCN 3

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chang Gyun; Sohn, Suk Whun; Sohn, Jong Joo; Seo, Jong Tae; Lee, Sang Keun [Korea Power Engineering Company, Inc., Seoul (Korea, Republic of); Kim, Yong Sung; Nam, Kyu Won; Jung, Yang Mook; Chae, Kyeong Sik; Koh, Bum Jae; Oh, Chul Sung; Park, Hee Chool [Korea Electric Power Corporation, Taejon (Korea, Republic of)

    1998-12-31

    The Load Rejection to House Load test at 50% power was successfully performed during the UCN 3 PAT period. In this test, all plant control systems automatically controlled the plant from 50% power to house load operation mode. The KISPAC code, which was used in the performance analysis during the design process of UCN 3 and 4, predictions of the test agreed with the measured data demonstrating the validity of the code as well as the completeness of the plant design. 3 refs., 8 figs., 1 tab. (Author)

  2. Multistage stochastic optimization

    CERN Document Server

    Pflug, Georg Ch

    2014-01-01

    Multistage stochastic optimization problems appear in many ways in finance, insurance, energy production and trading, logistics and transportation, among other areas. They describe decision situations under uncertainty and with a longer planning horizon. This book contains a comprehensive treatment of today’s state of the art in multistage stochastic optimization.  It covers the mathematical backgrounds of approximation theory as well as numerous practical algorithms and examples for the generation and handling of scenario trees. A special emphasis is put on estimation and bounding of the modeling error using novel distance concepts, on time consistency and the role of model ambiguity in the decision process. An extensive treatment of examples from electricity production, asset liability management and inventory control concludes the book

  3. Object Tracking Vision System for Mapping the UCN τ Apparatus Volume

    Science.gov (United States)

    Lumb, Rowan; UCNtau Collaboration

    2016-09-01

    The UCN τ collaboration has an immediate goal to measure the lifetime of the free neutron to within 0.1%, i.e. about 1 s. The UCN τ apparatus is a magneto-gravitational ``bottle'' system. This system holds low energy, or ultracold, neutrons in the apparatus with the constraint of gravity, and keeps these low energy neutrons from interacting with the bottle via a strong 1 T surface magnetic field created by a bowl-shaped array of permanent magnets. The apparatus is wrapped with energized coils to supply a magnetic field throughout the ''bottle'' volume to prevent depolarization of the neutrons. An object-tracking stereo-vision system will be presented that precisely tracks a Hall probe and allows a mapping of the magnetic field throughout the volume of the UCN τ bottle. The stereo-vision system utilizes two cameras and open source openCV software to track an object's 3-d position in space in real time. The desired resolution is +/-1 mm resolution along each axis. The vision system is being used as part of an even larger system to map the magnetic field of the UCN τ apparatus and expose any possible systematic effects due to field cancellation or low field points which could allow neutrons to depolarize and possibly escape from the apparatus undetected. Tennessee Technological University.

  4. Design of a 4 1/2 stage turbine with a stage loading factor of 4.66 and high specific work output

    Science.gov (United States)

    Webster, P. F.

    1976-01-01

    The aerodynamic design of a highly loaded multistage fan drive turbine is discussed. Turbine flowpath and airfoil sections are presented along with respective pressure and velocity distributions. Vibrational modes are identified in the expected turbine operating range.

  5. Coupling methods for multistage sampling

    OpenAIRE

    Chauvet, Guillaume

    2015-01-01

    Multistage sampling is commonly used for household surveys when there exists no sampling frame, or when the population is scattered over a wide area. Multistage sampling usually introduces a complex dependence in the selection of the final units, which makes asymptotic results quite difficult to prove. In this work, we consider multistage sampling with simple random without replacement sampling at the first stage, and with an arbitrary sampling design for further stages. We consider coupling ...

  6. From crisis to sustainability - the UCN approach to doing business in Africa

    DEFF Research Database (Denmark)

    Lassen Hanan, Anne

    This paper highlights on the UCN approach to doing business in Africa. The UCN approach offers a specialization for social entrepreneurship and also helps to create new forms of partnership between Danish businesses and local companies in the focus countries (Ghana, Kenya, Tanzania, and Uganda......). The approach operates in line with international principles and guidelines for responsible business operations in a sustainable development perspective in Africa. The cardinal focus of the approach seeks to assist Danish businesses/researchers with some of the important considerations as to how investment...... strategies could fit into the focus countries in African working environments. Some of which include corporate governance, anti-corruption, bureaucracies of the law, the appropriate CSR/CSI methods, project/professional management, and cultural integration, gender, workers and disability rights....

  7. A Study on Fire Ignition Frequency of UCN 3 during Shutdown

    International Nuclear Information System (INIS)

    Kim, Kilyoo; Kang, DaeIl; Jang, Seung-Cheol

    2014-01-01

    A fire ignition frequency of UCN 3 during shutdown, i.e., during POS 3, 4, 5, 6 was calculated by using the new fire PSA method suggested in NUREG/CR-7114. As the fire ignition frequency during full power is calculated by the fixed ignition source and the transient ignition source, the one during shutdown is also calculated by the fixed and the transient ignition source. Since the fixed ignition source was already verified through the walkdown although the walkdown is for the fixed ignition source during full power, additional walkdown for the one during shutdown is not necessary. In the paper, how the fire ignition frequency of UCN 3 during shutdown was calculated is described. A fire ignition frequency of UCN 3 during shutdown, i.e., during POS 3, 4, 5, 6 was calculated by using the new fire PSA method suggested in NUREG/CR-7114. We make the transient ignition fire frequency of each BIN vary according to the daily work order of each POS

  8. 2D-FE throughflow method for multistage cooled turbines with subsonic and transonic flow. Final report; 2D-FE-Verfahren fuer die Kennfeldberechnung von vielstufigen Turbinen mit unter- und ueberkritischen Stufendruckverhaeltnissen mit variabler Kuehlluftzufuhr. Abschlussbericht zum Vorhaben 1.312

    Energy Technology Data Exchange (ETDEWEB)

    Riess, W.; Gehring, S.

    2000-07-01

    Throughflow calculations have proved to be useful tools for flow field analysis and performance prediction of multistage turbines during the design process. The advantages of this method are a very limited effort necessary for preparation and a short calculation time combined with sufficient accuracy. For the design of modern gas turbines it is necessary to consider the influence of modern cooling systems in these computations. The throughflow method presented here is based on the finite element method and includes extensions which consider radial transport processes and the influence of modern cooling systems. In order to calculate modern gas turbines with complex cooling systems the method considers arbitrary combinations of convection cooling, coolant ejection at the trailing edges, film cooling and coolant ejection at the end walls. The mixing of hot gas and coolant is calculated by simplified conservation laws. The raising mass flow due to coolant addition is considered by a modified definition of the stream function or in case of the coolant ejection at the end walls by modified boundary conditions. For a simpler application of the throughflow method the mass flow can be automatically adapted during the calculation in order to achieve a given pressure ratio. Due to the definition of the stream function in use, the mass flow can be corrected directly. Therefore the continuum equation is satisfied in the whole flow field during the calculation and the computing time is reduced. The reliability of the method is verified by calculations of a 1.5-stage turbine and the Siemens AG (KWU) high temperature gas turbine V84.3. In the 1.5-stage turbine coolant is ejected in front of the blading at different radii. The cooling system of the high temperature gas turbine consists of a combination of convective cooling and coolant ejection at the trailing edges. For both machines the calculations agree very well with the measurements. (orig.) [German

  9. Algunos logros del convenio internacional entre la UCN (Chile y ORSTOM (Francia - 1991-1997

    Directory of Open Access Journals (Sweden)

    1998-01-01

    Full Text Available QUELQUES ACQUIS DE LA CONVENTION INTERNATIONALE ENTRE L’UCN (CHILI ET L’ORSTOM (FRANCE - 1991-1997. Les quelques pages de cet article sont insuffisantes pour exposer in extenso la teneur des résultats scientifiques obtenus pendant six ans d’études, une partie étant reprise dans d’autres communications du colloque auxquelles on est prié de se référer. L’auteur présente simplement les acquis se rapportant aux divers objectifs spécifiques définis par la convention UCN-ORSTOM : organisation du travail, choix des secteurs étudiés, activités d’enseignement et de recherche, réalisation de thèses et de mémoires, obtention et diffusion des résultats, établissement de priorités pour les activités futures et bibliographie. Las pocas páginas de este artículo no permiten exponer in extenso el tenor de los resultados científicos obtenidos a lo largo de seis años de estudios, siendo una parte de ellos presentada en las demás comunicaciones del coloquio a las que se puede remitir. El autor no hace más que referirse al cumplimiento de los objetivos específicos definidos por el convenio UCN-ORSTOM: organización del trabajo, áreas de estudio, actividades académicas e investigadoras, realización de tesis y memorias, obtención y difusión de los resultados, planteamiento de prioridades para el futuro y bibliografía. SOME ATTAINMENT OF THE INTERNATIONAL COVENANT BETWEEN UCN (CHILE AND ORSTOM (FRANCE - 1991-1997. The few pages of this paper are insufficient to expose in extenso the contents of scientific results obtained after six years of studies you may have references of part of them exhibited in other papers of this event. The author presents only some attainment about the numerous specific objectives of the UCN-ORSTOM covenant: work organization, selection of the study areas, academic and research activities, realization of thesis and memories, obtaining and diffusion of results, establishment of future priorities and

  10. System design and optimization study of axial flow turbine applied in ...

    Indian Academy of Sciences (India)

    between parameters of the turbine and flows, three different types of turbines with ... and the water are run through a multi-stage hydro-turbine for producing electricity. ... to optimize the runner blade shape of a tubular turbine. ..... Ranade V V, Perrard M, Le Sauze N, Xuereb C and Bertrand J 2001 Trailing vortices of Rushton ...

  11. Computational analysis of a multistage axial compressor

    Science.gov (United States)

    Mamidoju, Chaithanya

    Turbomachines are used extensively in Aerospace, Power Generation, and Oil & Gas Industries. Efficiency of these machines is often an important factor and has led to the continuous effort to improve the design to achieve better efficiency. The axial flow compressor is a major component in a gas turbine with the turbine's overall performance depending strongly on compressor performance. Traditional analysis of axial compressors involves throughflow calculations, isolated blade passage analysis, Quasi-3D blade-to-blade analysis, single-stage (rotor-stator) analysis, and multi-stage analysis involving larger design cycles. In the current study, the detailed flow through a 15 stage axial compressor is analyzed using a 3-D Navier Stokes CFD solver in a parallel computing environment. Methodology is described for steady state (frozen rotor stator) analysis of one blade passage per component. Various effects such as mesh type and density, boundary conditions, tip clearance and numerical issues such as turbulence model choice, advection model choice, and parallel processing performance are analyzed. A high sensitivity of the predictions to the above was found. Physical explanation to the flow features observed in the computational study are given. The total pressure rise verses mass flow rate was computed.

  12. Biochemical characterization of the deafness-associated mitochondrial tRNASer(UCN) A7445G mutation in osteosarcoma cell cybrids

    International Nuclear Information System (INIS)

    Li Xiaoming; Zhang, Linda S.; Fischel-Ghodsian, Nathan; Guan Minxin

    2005-01-01

    The deafness-associated A7445G mutation in the precursor of mitochondrial tRNA Ser(UCN) has been identified in several pedigrees from different ethnic backgrounds. To determine the role of nuclear background in the biochemical manifestation associated with the A7445G mutation, we performed a biochemical characterization of this mutation using cybrids constructed by transferring mitochondria from lymphoblastoid cell lines derived from a New Zealand family into human osteosarcoma mtDNA-less (ρ 0 ) cells. Compared with three control cybrids, three cybrids derived from an affected matrilineal relative carrying the homoplasmic A7445G mutation exhibited ∼38-57% decrease in the steady-state level of tRNA Ser(UCN) , which is less reduced levels than in lymphoblastoid cells in the previous study. Furthermore, ∼22% reduction in the level of aminoacylation of tRNA Ser(UCN) was observed in the mutant cybrid cells. Interestingly, ∼60-63% decrease of steady-state level of ND6 gene, which belongs to the same precursor as that of tRNA Ser(UCN) , in cybrid cell lines carrying the A7445G mutation, is more than that observed in lymphoblastoid cells. These observations strongly point out a mechanistic link between the processing defect of the tRNA Ser(UCN) precursor and decreased stability of ND6 mRNA precursor. These results also imply the influence of nuclear background on the biochemical phenotype associated with the A7445G mutation

  13. Results and Systematic Studies of the UCN Lifetime Experiment at NIST

    Science.gov (United States)

    Huffer, Craig Reeves

    The neutron beta-decay lifetime is important in understanding weak interactions in the framework of the Standard Model, and it is an input to nuclear astrophysics and Big Bang Nucleosynthesis. Current measurements of the neutron beta-decay lifetime disagree, which has motivated additional experiments that are sensitive to different sets of systematic effects. An effort continues at the NIST Center for Neutron Research (NCNR) to improve the statistical and systematic limitations of an experiment to measure the neutron beta-decay lifetime using magnetically trapped UCN. In the experiment, a monoenergetic 0:89 nm cold neutron is incident on a superfluid 4He target within the minimum field region of an Ioffe type magnetic trap. Some of the neutrons are subsequently downscattered by single phonons in the helium to low energies (≈ 200 neV), and those in the appropriate spin state become trapped. The inverse process, upscattering of UCN, is suppressed by the low phonon density in the analysis, data, and systematics will be discussed. After accounting for the systematic effects the measured lifetime disagrees with the current PDG mean neutron beta-decay lifetime by about 9 of our standard deviations, which is a strong indication of unaccounted for systematic effects. Additional 3He contamination will be shown to be the most likely candidate for the additional systematic shift, which motivated the commissioning and initial operation of a heat flush purifier for purifying additional 4He. This work ends with a description of the 4He purifier and its performance.

  14. The method of UCN "small heating" measurement in the big gravitational spectrometer (BGS) and studies of this effect on Fomblin oil Y-HVAC 18/8

    Science.gov (United States)

    Nesvizhevsky, V. V.; Voronin, A. Yu.; Lambrecht, A.; Reynaud, S.; Lychagin, E. V.; Muzychka, A. Yu.; Nekhaev, G. V.; Strelkov, A. V.

    2018-02-01

    The Big Gravitational Spectrometer (BGS) takes advantage of the strong influence of the Earth's gravity on the motion of ultracold neutrons (UCNs) that makes it possible to shape and measure UCN spectra. We optimized the BGS to investigate the "small heating" of UCNs, that is, the inelastic reflection of UCNs from a surface accompanied by an energy change comparable with the initial UCN energy. UCNs whose energy increases are referred to as "Vaporized UCNs" (VUCNs). The BGS provides the narrowest UCN spectra of a few cm and the broadest "visible" VUCN energy range of up to ˜150 cm (UCN energy is given in units of its maximum height in the Earth's gravitational field, where 1.00 cm ≈ 1.02 neV). The dead-zone between the UCN and VUCN spectra is the narrowest ever achieved (a few cm). We performed measurements with and without samples without breaking vacuum. BGS provides the broadest range of temperatures (77-600 K) and the highest sensitivity to the small heating effect, up to ˜10-8 per bounce, i.e., two orders of magnitude higher than the sensitivity of alternative methods. We describe the method to measure the probability of UCN "small heating" using the BGS and illustrate it with a study of samples of the hydrogen-free oil Fomblin Y-HVAC 18/8. The data obtained are well reproducible, do not depend on sample thickness, and do not evolve over time. The measured model-independent probability P+ of UCN small heating from an energy "mono-line" 30.2 ± 2.5 cm to the energy range 35-140 cm is in the range (1.05 ±0.02s t a t )×1 0-5-(1.31 ±0.24s t a t )×1 0-5 at a temperature of 24 °C. The associated systematic uncertainty would disappear if a VUCN spectrum shape were known, for instance, from a particular model of small heating. This experiment provides the most precise and reliable value of small heating probability on Fomblin measured so far. These results are of importance for studies of UCN small heating as well as for analyzing and designing neutron

  15. The method of UCN "small heating" measurement in the big gravitational spectrometer (BGS) and studies of this effect on Fomblin oil Y-HVAC 18/8.

    Science.gov (United States)

    Nesvizhevsky, V V; Voronin, A Yu; Lambrecht, A; Reynaud, S; Lychagin, E V; Muzychka, A Yu; Nekhaev, G V; Strelkov, A V

    2018-02-01

    The Big Gravitational Spectrometer (BGS) takes advantage of the strong influence of the Earth's gravity on the motion of ultracold neutrons (UCNs) that makes it possible to shape and measure UCN spectra. We optimized the BGS to investigate the "small heating" of UCNs, that is, the inelastic reflection of UCNs from a surface accompanied by an energy change comparable with the initial UCN energy. UCNs whose energy increases are referred to as "Vaporized UCNs" (VUCNs). The BGS provides the narrowest UCN spectra of a few cm and the broadest "visible" VUCN energy range of up to ∼150 cm (UCN energy is given in units of its maximum height in the Earth's gravitational field, where 1.00 cm ≈ 1.02 neV). The dead-zone between the UCN and VUCN spectra is the narrowest ever achieved (a few cm). We performed measurements with and without samples without breaking vacuum. BGS provides the broadest range of temperatures (77-600 K) and the highest sensitivity to the small heating effect, up to ∼10 -8 per bounce, i.e., two orders of magnitude higher than the sensitivity of alternative methods. We describe the method to measure the probability of UCN "small heating" using the BGS and illustrate it with a study of samples of the hydrogen-free oil Fomblin Y-HVAC 18/8. The data obtained are well reproducible, do not depend on sample thickness, and do not evolve over time. The measured model-independent probability P + of UCN small heating from an energy "mono-line" 30.2 ± 2.5 cm to the energy range 35-140 cm is in the range 1.05±0.02 stat ×10 -5 -1.31±0.24 stat ×10 -5 at a temperature of 24 °C. The associated systematic uncertainty would disappear if a VUCN spectrum shape were known, for instance, from a particular model of small heating. This experiment provides the most precise and reliable value of small heating probability on Fomblin measured so far. These results are of importance for studies of UCN small heating as well as for analyzing and designing neutron lifetime

  16. Gas turbine

    International Nuclear Information System (INIS)

    Yang, Ok Ryong

    2004-01-01

    This book introduces gas turbine cycle explaining general thing of gas turbine, full gas turbine cycle, Ericson cycle and Brayton cycle, practical gas turbine cycle without pressure loss, multiaxial type gas turbine cycle and special gas turbine cycle, application of basic theory on a study on suction-cooling gas turbine cycle with turbo-refrigerating machine using the bleed air, and general performance characteristics of the suction-cooling gas turbine cycle combined with absorption-type refrigerating machine.

  17. Cross species association examination of UCN3 and CRHR2 as potential pharmacological targets for antiobesity drugs.

    Directory of Open Access Journals (Sweden)

    Zhihua Jiang

    Full Text Available BACKGROUND: Obesity now constitutes a leading global public health problem. Studies have shown that insulin resistance affiliated with obesity is associated with intramyocellular lipid (IMCL accumulation. Therefore, identification of genes associated with the phenotype would provide a clear target for pharmaceutical intervention and care for the condition. We hypothesized that urocortin 3 (UCN3 and corticotropin-releasing hormone receptor 2 (CRHR2 are associated with IMCL and subcutaneous fat depth (SFD, because the corticotropin-releasing hormone family of peptides are capable of strong anorectic and thermogenic effects. METHODOLOGY/PRINCIPAL FINDINGS: We annotated both bovine UCN3 and CRHR2 genes and identified 12 genetic mutations in the former gene and 5 genetic markers in the promoter region of the latter gene. Genotyping of these 17 markers on Wagyu times Limousin F(2 progeny revealed significant associations between promoter polymorphisms and SFD (P = 0.0203-0.0685 and between missense mutations of exon 2 and IMCL (P = 0.0055-0.0369 in the bovine UCN3 gene. The SFD associated promoter SNPs caused a gain/loss of 12 potential transcription regulatory binding sites, while the IMCL associated coding SNPs affected the secondary structure of UCN3 mRNA. However, none of five polymorphisms in CRHR2 gene clearly co-segregated with either trait in the population (P>0.6000. CONCLUSIONS/SIGNIFICANCE: Because UCN3 is located on human chromosome 10p15.1 where quantitative trait loci for obesity have been reported, our cross species study provides further evidence that it could be proposed as a potential target for developing antiobesity drugs. None of the markers in CRHR2 was associated with obesity-type traits in cattle, which is consistent with findings in human. Therefore, CRHR2 does not lend itself to the development of antiobesity drugs.

  18. UCN up-scattering as a source of highly intense monochromatic pulsed beams

    International Nuclear Information System (INIS)

    Rauch, H.; Geltenborg, P.; Zimmer, O.

    2011-01-01

    The present proposal opens new possibilities to increase the usable neutron flux by advanced neutron cooling and phase space transformation methods. Thus a new instrument should be installed where the available neutron flux is used more efficiently. The essential point is an increase of phase space density and brilliance due to a more effective production of ultra-cold neutrons and a following transformation of these neutrons to higher energies. Recently reported progresses in the production of UCN's and in the up-scattering of such neutrons make the time mature to step towards a new method to produce high intense pulsed neutron beams. The up-scattering is made by fast moving Bragg crystals

  19. Interconnected Levels of Multi-Stage Marketing

    DEFF Research Database (Denmark)

    Vedel, Mette; Geersbro, Jens; Ritter, Thomas

    2012-01-01

    different levels of multi-stage marketing and illustrates these stages with a case study. In addition, a triadic perspective is introduced as an analytical tool for multi-stage marketing research. The results from the case study indicate that multi-stage marketing exists on different levels. Thus, managers...... must not only decide in general on the merits of multi-stage marketing for their firm, but must also decide on which level they will engage in multi-stage marketing. The triadic perspective enables a rich and multi-dimensional understanding of how different business relationships influence each other...... in a multi-stage marketing context. This understanding assists managers in assessing and balancing different aspects of multi- stage marketing. The triadic perspective also offers avenues for further research....

  20. A Pilot Study on Applying Option 2 to Two Systems in the UCN 3, 4 - HPSI, ESWS

    International Nuclear Information System (INIS)

    Kim, Kil Yoo; Kang, D. I.; Hwang, M J.; Yang, J. E.

    2005-04-01

    This report describes the Option 2 method applied to high pressure safety injection system(HPSI) and essential service water system(ESW) UCN 3,4 based on the U.S NEI 00-04 Option 2 methodology. Thus, in the Option 2 applications under the 10 CFR 50.69 requirement, the special treatment requirements for 'RISC-3' SSCs could be relaxed, while the regulartory requirements for 'RISC-2' SSCs will be enhanced. The results of Option 2 applications for the two systems of UCN 3,4 show that 161 out of 277 safety related SSCs can be treated with relaxed requirements in the HPSI, while 20 non-safety related SSCs should be treated with special treatment requirements. Also, in the ESW, special treatment requirements for the 121 out of 238 safety related SSCs can be relaxed, and new special treatments are required for 4 non-safety related SSCs

  1. Turbinate surgery

    Science.gov (United States)

    Turbinectomy; Turbinoplasty; Turbinate reduction; Nasal airway surgery; Nasal obstruction - turbinate surgery ... There are several types of turbinate surgery: Turbinectomy: All or ... This can be done in several different ways, but sometimes a ...

  2. Efficiency increase in ship's primal energy system using a multistage compression with intercooling

    Directory of Open Access Journals (Sweden)

    Landeka Petar

    2016-01-01

    Full Text Available This paper focuses on an analysis of the potential increase of efficiency in ship's primal energy system using a turbocharger with multistage compression with intercooling, and diverting a greater flow of exhaust gases to power turbine of waste heat recovery system (WHR. Analysis of potential efficiency increase has been made for various stages of compression for a 100 % main engine load, and an analysis of five stage compression with intercooling for a main engine load between 50% and 100%.

  3. A Pilot Study on Applying Risk Informed Application Option 2 to Two Systems in UCN 3

    International Nuclear Information System (INIS)

    Kim, Kil Yoo; Hwang, Mee Jeong; Yang, Joon Eon

    2005-01-01

    To reduce the unnecessary burden of a regulation, NRC prepared three options for the risk informed regulatory framework known as Option 1, Option 2 and Option 3. In Option 2, all safety related Structure, System and Components (SSCs) and non-safety related SSCs are evaluated from a safety point of view, and the low safety significant SSCs belonging to the safety related group are called 'Risk Informed Safety Class (RISC) - 3' SSCs. The 'RISC-3' SSCs can be exempted from the special treatment requirements such as a seismic and environmental requirement, of 10 CFR 50. For Option 2, 10 CFR 50.69 was issued by US NRC, and NEI 00-04 was prepared by US industry as a categorization guideline for 10 CFR 50.69, and US NRC endorsed the NEI 00-04 methodology for Option 2 in Reg. Guide 1.201. This paper describes the Option 2 method applied to the high pressure safety injection system (HPSI) and the essential service water system (ESW) of UCN 3

  4. A Pilot Study on Applying Risk Informed Application Option 2 to Six Systems in UCN 3

    International Nuclear Information System (INIS)

    Kim, Kil-Yoo; Yang, Joon-Eon; Lee, Young-Joo; Chung, Hye-Won

    2007-01-01

    To reduce the unnecessary burden of a regulation, NRC prepared three options for the risk informed regulatory framework known as Option 1, Option 2 and Option 3. In Option 2, all safety related Structure, System and Components (SSCs) and non-safety related SSCs are evaluated from a safety point of view, and the low safety significant SSCs belonging to the safety related group are called 'Risk Informed Safety Class (RISC) - 3' SSCs. The 'RISC-3' SSCs can be exempted from the special treatment requirements such as a seismic and environmental requirement, of 10 CFR 50. Two years ago, a paper was published which described the Option 2 method applied to the high pressure safety injection system (HPSI) and the essential service water system (ESW) of UCN 3. However, this paper describes the results when Option 2 is applied to the other 4 systems such as a low pressure safety injection system(LPSI), safety depressurization system(SDS), instrument air system(IAS), safety injection tank(SIT). First of all, this paper includes the results from the importance analysis in view of a Fire PSA and Level 2 PSA

  5. An ultracold neutron (UCN) detector with Ti/ sup 6 LiF multi-layer converter and sup 5 sup 8 Ni reflector

    CERN Document Server

    Maier-Komor, P; Bergmaier, A; Dollinger, G; Paul, S; Petzoldt, G; Schott, W

    2002-01-01

    High efficient detectors for ultracold neutrons (UCN) must be developed for the new high flux neutron source Forschungsreaktor Muenchen II (FRM II). On silicon PIN diodes 76 mu g/cm sup 2 sup 5 sup 8 Ni was deposited as a UCN reflector. On this 100 double layers of sup n sup a sup t Ti (4.7 mu g/cm sup 2) and sup 6 LiF (1.8 mu g/cm sup 2) were deposited to function as a UCN converter. On top of this, 33 double layers of sup n sup a sup t Ti (3.4 mu g/cm sup 2) and sup 6 LiF (0.92 mu g/cm sup 2) were condensed in addition to provide sensitivity to very low-energy UCN. Finally, 6.0 mu g/cm sup 2 sup n sup a sup t V was deposited to protect the multi-layers. Vanadium has nearly zero optical potential for UCN and thus should not hinder their transmission. Since no expensive isotopes were involved, a source to substrate distance of 24 cm could be chosen, leading to excellent uniformity. The setup designed for deposition under ultrahigh vacuum conditions and the evaporation procedures are described.

  6. Design and numerical study of turbines operating with MDM as working fluid

    Science.gov (United States)

    Klonowicz, Piotr; Surwiło, Jan; Witanowski, Łukasz; Suchocki, Tomasz K.; Kozanecki, Zbigniew; Lampart, Piotr

    2015-12-01

    Design processes and numerical simulations have been presented for a few cases of turbines designated to work in ORC systems. The chosen working fluid isMDM. The considered design configurations include single stage centripetal reaction and centrifugal impulse turbines as well as multistage axial turbines. The power outputs vary from about 75 kW to 1 MW. The flow in single stage turbines is supersonic and requires special design of blades. The internal efficiencies of these configurations exceed 80% which is considered high for these type of machines. The efficiency of axial turbines exceed 90%. Possible turbine optimization directions have been also outlined in the work.

  7. Split-plot designs for multistage experimentation

    DEFF Research Database (Denmark)

    Kulahci, Murat; Tyssedal, John

    2016-01-01

    at the same time will be more efficient. However, there have been only a few attempts in the literature to provide an adequate and easy-to-use approach for this problem. In this paper, we present a novel methodology for constructing two-level split-plot and multistage experiments. The methodology is based...... be accommodated in each stage. Furthermore, split-plot designs for multistage experiments with good projective properties are also provided....

  8. Development of new NSSS thermal-hydraulic model for Korean standard nuclear power plant(UCN-3/4) simulator

    International Nuclear Information System (INIS)

    Kim, Kyung Doo; Jeong, Jae Jun

    2001-09-01

    The NSSS thermal-hydraulic programs installed in the domestic full-scope power plant simulators were provided in early 1980s by foreign vendors. Because of limited computational capability at that time, they usually adopt very simplified physical models for a real-time simulation of NSSS thermal-hydraulic phenomena, which entails inaccurate results and the possibility of so-called 'negative training', especially for complicated two-phase flows in the reactor coolant system. To resolve the problem, we developed a realistic NSSS T/H program (named 'ARTS-UCN' code) for the improvement of the Korean Standard Nuclear Power Plant full-scope simulator. ARTS Code, developed as an NSSS T/H model for the KNPEC no. 2 simulator using the RETRAN03 code, was selected as a reference code for ARTS-UCN code development. For the development of ARTS, the followings have been performed: - Improvement of the robustness of RETRAN - Improvement of the real-time simulation capability of RETRAN - Optimum input data generation for the NSSS simulation - New model development that cannot be efficiently modeled by RETRAN - Assessment of the ARTS code. The systematic assessment of ARTS has been conducted in both personal computers (Windows 98, Visual fortran) and the simulator development environment (Windows NT, GSE simulator development tool). The results were resonable in terms of accuracy, real-time simulation and robustness

  9. Hydraulic turbines

    International Nuclear Information System (INIS)

    Meluk O, G.

    1998-01-01

    The hydraulic turbines are defined according to the specific speed, in impulse turbines and in reaction turbines. Currently, the Pelton turbines (of impulse) and the Francis and Kaplan turbines (of reaction), they are the most important machines in the hydroelectric generation. The hydraulic turbines are capable of generating in short times, large powers, from its loads zero until the total load and reject the load instantly without producing damages in the operation. When the hydraulic resources are important, the hydraulic turbines are converted in the axle of the electric system. Its combination with thermoelectric generation systems, it allow the continuing supply of the variations in demand of energy system. The available hydraulic resource in Colombia is of 93085 MW, of which solely 9% is exploited, become 79% of all the electrical country generation, 21% remaining is provided by means of the thermoelectric generation

  10. Mutational analysis of the mitochondrial 12S rRNA and tRNASer(UCN) genes in Tunisian patients with nonsyndromic hearing loss

    International Nuclear Information System (INIS)

    Mkaouar-Rebai, Emna; Tlili, Abdelaziz; Masmoudi, Saber; Louhichi, Nacim; Charfeddine, Ilhem; Amor, Mohamed Ben; Lahmar, Imed; Driss, Nabil; Drira, Mohamed; Ayadi, Hammadi; Fakhfakh, Faiza

    2006-01-01

    We explored the mitochondrial 12S rRNA and the tRNA Ser(UCN) genes in 100 Tunisian families affected with NSHL and in 100 control individuals. We identified the mitochondrial A1555G mutation in one out of these 100 families and not in the 100 control individuals. Members of this family harbouring the A1555G mutation showed phenotypic heterogeneity which could be explained by an eventual nuclear-mitochondrial interaction. So, we have screened three nuclear genes: GJB2, GJB3, and GJB6 but we have not found correlation between the phenotypic heterogeneity and variants detected in these genes. We explored also the entire mitochondrial 12S rRNA and the tRNA Ser(UCN) genes. We detected five novel polymorphisms: T742C, T794A, A813G, C868T, and C954T, and 12 known polymorphisms in the mitochondrial 12S rRNA gene. None of the 100 families or the 100 controls were found to carry mutations in the tRNA Ser(UCN) gene. We report here First mutational screening of the mitochondrial 12S rRNA and the tRNA Ser(UCN) genes in the Tunisian population which describes the second family harbouring the A1555G mutation in Africa and reveals novel polymorphisms in the mitochondrial 12S rRNA gene

  11. Experiments for Multi-Stage Processes

    DEFF Research Database (Denmark)

    Tyssedal, John; Kulahci, Murat

    2015-01-01

    Multi-stage processes are very common in both process and manufacturing industries. In this article we present a methodology for designing experiments for multi-stage processes. Typically in these situations the design is expected to involve many factors from different stages. To minimize...... the required number of experimental runs, we suggest using mirror image pairs of experiments at each stage following the first. As the design criterion, we consider their projectivity and mainly focus on projectivity 3 designs. We provide the methodology for generating these designs for processes with any...

  12. ATWS analysis for total loss of feedwater sequence in UCN 3 and 4

    International Nuclear Information System (INIS)

    Park, S. H.; Song, Y. M.; Kim, D. H.; Kim, S. D.; Park, S. Y.

    1999-01-01

    ATWS is a trip-failed severe accident initiated from the transients like a turbine trip, a control bank withdrawal, and a loss of feedwater which are expected to occur comparatively often (one or two occurrences / year). In this study, an ATWS sequence in Ulchin 3 and 4 is analyzed and the effects of the important systems are studied for accident management purpose using a MIDAS/PK computer code. The MIDAS/PK code has been developed via coupling a point kinetics module with the MELCOR code. The code calculates a primary peak pressure of about 24MPa at 240 seconds for the ATWS initiated by a TLOF (Total Loss of Feedwater) transient. Along with the basic ATWS analysis, several sensitivity runs are performed. From these, the turbines and the safety depressurization system (SDS) are judged to be important. The turbine trip resulting in a loss of offsite power and a RCP trip, degrades primary heat transfer to the secondary sides, and in turn, increases primary coolant temperature which reduces the reactor power due to the negative moderator temperature coefficient. Manual operation of SDS has an effect to lower the primary peak pressure considerably via supplementary depressurization in addition to the PORVs

  13. Multistage feature extraction for accurate face alignment

    NARCIS (Netherlands)

    Zuo, F.; With, de P.H.N.

    2004-01-01

    We propose a novel multistage facial feature extraction approach using a combination of 'global' and 'local' techniques. At the first stage, we use template matching, based on an Edge-Orientation-Map for fast feature position estimation. Using this result, a statistical framework applying the Active

  14. Interconnected levels of multi-stage marketing: A triadic approach

    OpenAIRE

    Vedel, Mette; Geersbro, Jens; Ritter, Thomas

    2012-01-01

    Multi-stage marketing gains increasing attention as knowledge of and influence on the customer's customer become more critical for the firm's success. Despite this increasing managerial relevance, systematic approaches for analyzing multi-stage marketing are still missing. This paper conceptualizes different levels of multi-stage marketing and illustrates these stages with a case study. In addition, a triadic perspective is introduced as an analytical tool for multi-stage marketing research. ...

  15. Multi-stage combustion using nitrogen-enriched air

    Science.gov (United States)

    Fischer, Larry E.; Anderson, Brian L.

    2004-09-14

    Multi-stage combustion technology combined with nitrogen-enriched air technology for controlling the combustion temperature and products to extend the maintenance and lifetime cycles of materials in contact with combustion products and to reduce pollutants while maintaining relatively high combustion and thermal cycle efficiencies. The first stage of combustion operates fuel rich where most of the heat of combustion is released by burning it with nitrogen-enriched air. Part of the energy in the combustion gases is used to perform work or to provide heat. The cooled combustion gases are reheated by additional stages of combustion until the last stage is at or near stoichiometric conditions. Additional energy is extracted from each stage to result in relatively high thermal cycle efficiency. The air is enriched with nitrogen using air separation technologies such as diffusion, permeable membrane, absorption, and cryogenics. The combustion method is applicable to many types of combustion equipment, including: boilers, burners, turbines, internal combustion engines, and many types of fuel including hydrogen and carbon-based fuels including methane and coal.

  16. Multistage Stochastic Programming via Autoregressive Sequences

    Czech Academy of Sciences Publication Activity Database

    Kaňková, Vlasta

    2007-01-01

    Roč. 15, č. 4 (2007), s. 99-110 ISSN 0572-3043 R&D Projects: GA ČR GA402/07/1113; GA ČR(CZ) GA402/06/0990; GA ČR GD402/03/H057 Institutional research plan: CEZ:AV0Z10750506 Keywords : Economic proceses * Multistage stochastic programming * autoregressive sequences * individual probability constraints Subject RIV: BB - Applied Statistics, Operational Research

  17. Handling Imbalanced Data Sets in Multistage Classification

    Science.gov (United States)

    López, M.

    Multistage classification is a logical approach, based on a divide-and-conquer solution, for dealing with problems with a high number of classes. The classification problem is divided into several sequential steps, each one associated to a single classifier that works with subgroups of the original classes. In each level, the current set of classes is split into smaller subgroups of classes until they (the subgroups) are composed of only one class. The resulting chain of classifiers can be represented as a tree, which (1) simplifies the classification process by using fewer categories in each classifier and (2) makes it possible to combine several algorithms or use different attributes in each stage. Most of the classification algorithms can be biased in the sense of selecting the most populated class in overlapping areas of the input space. This can degrade a multistage classifier performance if the training set sample frequencies do not reflect the real prevalence in the population. Several techniques such as applying prior probabilities, assigning weights to the classes, or replicating instances have been developed to overcome this handicap. Most of them are designed for two-class (accept-reject) problems. In this article, we evaluate several of these techniques as applied to multistage classification and analyze how they can be useful for astronomy. We compare the results obtained by classifying a data set based on Hipparcos with and without these methods.

  18. Gas turbines

    Energy Technology Data Exchange (ETDEWEB)

    Farahan, E.; Eudaly, J.P.

    1978-10-01

    This evaluation provides performance and cost data for commercially available simple- and regenerative-cycle gas turbines. Intercooled, reheat, and compound cycles are discussed from theoretical basis only, because actual units are not currently available, except on a special-order basis. Performance characteristics investigated include unit efficiency at full-load and off-design conditions, and at rated capacity. Costs are tabulated for both simple- and regenerative-cycle gas turbines. The output capacity of the gas turbines investigated ranges from 80 to 134,000 hp for simple units and from 12,000 to 50,000 hp for regenerative units.

  19. TAS1R3 and UCN2 Transcript Levels in Blood Cells Are Associated With Sugary and Fatty Food Consumption in Children.

    Science.gov (United States)

    Priego, T; Sánchez, J; Picó, C; Ahrens, W; De Henauw, S; Kourides, Y; Lissner, L; Molnár, D; Moreno, L A; Russo, P; Siani, A; Veidebaum, T; Palou, A

    2015-09-01

    New types of dietary exposure biomarkers are needed to implement effective strategies for obesity prevention in children. Of special interest are biomarkers of consumption of food rich in simple sugars and fat because their intake has been associated with obesity development. Peripheral blood cells (PBCs) represent a promising new tool for identifying novel, transcript-based biomarkers. This study aimed to study potential associations between the transcripts of taste receptor type 1 member 3 (TAS1R3) and urocortin II (UCN2) genes in PBCs and the frequency of sugary and fatty food consumption in children. Four hundred sixty-three children from the IDEFICS cohort were selected to include a similar number of boys and girls, both normal-weight and overweight, belonging to eight European countries. Anthropometric parameters (measured at baseline and in a subset of 193 children after 2 years), food consumption frequency and transcript levels of TAS1R3 and UCN2 genes in PBCs were measured. Children with low-frequency consumption of sugary foods displayed higher TAS1R3 expression levels with respect to those with intermediate or high frequency. In turn, children with high-frequency consumption of fatty foods showed lower UCN2 expression levels with respect to those with low or intermediate frequency. Moreover, transcripts of TAS1R3 were related with body mass index and fat-mass changes after a 2-year follow-up period, with low expression levels of this gene being related with increased fat accumulation over time. The transcripts of TAS1R3 and UCN2 in PBCs may be considered potential biomarkers of consumption of sugary and fatty food, respectively, to complement data of food-intake questionnaires.

  20. Pelton turbines

    CERN Document Server

    Zhang, Zhengji

    2016-01-01

    This book concerns the theoretical foundations of hydromechanics of Pelton turbines from the engineering viewpoint. For reference purposes, all relevant flow processes and hydraulic aspects in a Pelton turbine have been analyzed completely and systematically. The analyses especially include the quantification of all possible losses existing in the Pelton turbine and the indication of most available potential for further enhancing the system efficiency. As a guideline the book therefore supports further developments of Pelton turbines with regard to their hydraulic designs and optimizations. It is thus suitable for the development and design engineers as well as those working in the field of turbo machinery. Many laws described in the book can also be directly used to simplify aspects of computational fluid dynamics (CFD) or to develop new computational methods. The well-executed examples help better understand the related flow mechanics.

  1. Prediction of the secondary structure of the mitochondrial tRNASer (UCN) of Lutzomyia hartmanni (Diptera: Psychodidae)

    International Nuclear Information System (INIS)

    Perez Doria, Alveiro; Bejarano, Eduar E

    2011-01-01

    Lutzomyia (Helcocyrtomyia) hartmanni is a sand fly that has been implicated in the transmission of Leishmania (Viannia) colombiensis, an etiologic agent of cutaneous Leishmaniasis in Colombia. The objective of this work was to explore the potential usefulness of the mitochondrial serine transfer RNA (UCN) (tRNASer) in the taxonomic determination of L. hartmanni. Mitochondrial DNA was extracted, amplified and sequenced from entomological material collected in Envigado, Antioquia, Colombia. The tRNASer gene length was 68 nucleotide pairs, with an average adenine-thymine content of 80.9%. The studied tRNASer differs from other sand fly tRNASer known to date, on the basis of its primary and secondary structure. The observed number of intrachain base pairing was 7 in the acceptor arm, 3 in the dihydrouridine (DHU) arm, 5 in the anticodon arm, and 5 in the ribothymidine-pseudouridine-cytosine (TC) arm. The size of the DHU, anticodon, variable and TC loops was estimated to be 5, 7, 4, and 8 nucleotides, respectively. The notorious absence of non-Watson-Crick base pairs in the four arms of the tRNASer distinguishes that of L. hartmanni from others Lutzomyia spp.

  2. Reducing Delay in Diagnosis: Multistage Recommendation Tracking.

    Science.gov (United States)

    Wandtke, Ben; Gallagher, Sarah

    2017-11-01

    The purpose of this study was to determine whether a multistage tracking system could improve communication between health care providers, reducing the risk of delay in diagnosis related to inconsistent communication and tracking of radiology follow-up recommendations. Unconditional recommendations for imaging follow-up of all diagnostic imaging modalities excluding mammography (n = 589) were entered into a database and tracked through a multistage tracking system for 13 months. Tracking interventions were performed for patients for whom completion of recommended follow-up imaging could not be identified 1 month after the recommendation due date. Postintervention compliance with the follow-up recommendation required examination completion or clinical closure (i.e., biopsy, limited life expectancy or death, or subspecialist referral). Baseline radiology information system checks performed 1 month after the recommendation due date revealed timely completion of 43.1% of recommended imaging studies at our institution before intervention. Three separate tracking interventions were studied, showing effectiveness between 29.0% and 57.8%. The multistage tracking system increased the examination completion rate to 70.5% (a 52% increase) and reduced the rate of unknown follow-up compliance and the associated risk of delay in diagnosis to 13.9% (a 74% decrease). Examinations completed after tracking intervention generated revenue of 4.1 times greater than the labor cost. Performing sequential radiology recommendation tracking interventions can substantially reduce the rate of unknown follow-up compliance and add value to the health system. Unknown follow-up compliance is a risk factor for delay in diagnosis, a form of preventable medical error commonly identified in malpractice claims involving radiologists and office-based practitioners.

  3. Multi-stage wake-field accelerator

    International Nuclear Information System (INIS)

    Gai, Wei.

    1989-01-01

    In this paper we propose a multi-stage wake field acceleration scheme to overcome the low transformer ratio problem and still provide high accelerating gradients. The idea is very simple. We use a train of several electron bunches from a linear accelerator (main linac) with well defined separations between the bunches (tens of ns) to drive wake field devices. Here we have made the assumption that the wake field devices are available, whether plasma, iris-loaded metallic or dielectric wake field structures. 10 refs

  4. Wind turbine

    Science.gov (United States)

    Cheney, Jr., Marvin C.

    1982-01-01

    A wind turbine of the type having an airfoil blade (15) mounted on a flexible beam (20) and a pitch governor (55) which selectively, torsionally twists the flexible beam in response to wind turbine speed thereby setting blade pitch, is provided with a limiter (85) which restricts unwanted pitch change at operating speeds due to torsional creep of the flexible beam. The limiter allows twisting of the beam by the governor under excessive wind velocity conditions to orient the blades in stall pitch positions, thereby preventing overspeed operation of the turbine. In the preferred embodiment, the pitch governor comprises a pendulum (65,70) which responds to changing rotor speed by pivotal movement, the limiter comprising a resilient member (90) which engages an end of the pendulum to restrict further movement thereof, and in turn restrict beam creep and unwanted blade pitch misadjustment.

  5. Descripción del ARN de transferencia mitocondrial para Serina (UCN de Lutzomyia columbiana (Diptera, Psychodidae Description of the mitochondrial serine transfer RNA (UCN of Lutzomyia columbiana (Diptera, Psychodidae

    Directory of Open Access Journals (Sweden)

    Alveiro Pérez-Doria

    2008-01-01

    Full Text Available Lutzomyia columbiana es un flebotomíneo considerado como vector sospechoso de Leishmania mexicana y Leishmania braziliensis en Colombia. Este insecto pertenece al grupo verrucarum, que incluye algunos taxones isomórficos, lo que ha estimulado la búsqueda de marcadores moleculares que permitan, además de diferenciar las especies, estudiar sus relaciones de parentesco. En este artículo se describe por primera vez la estructura putativa del ARN de transferencia mitocondrial para serina que reconoce el codón UCN (ARNtSer de Lu. columbiana. El ADN genómico fue extraído, amplificado y secuenciado a partir de seis especímenes colectados con cebo humano. La estructura secundaria del ARNtSer fue inferida con el programa tRNAscan-SE 1.21. El gen ARNts consistió de 67 pares de bases (pb, encontrándose un solo haplotipo en los seis individuos secuenciados. El ARNtSer de Lu. columbiana mostró 7 apareamientos intracatenarios en el brazo aceptor del aminoácido, 3 en el brazo dihidrouridina (DHU, 5 en el brazo del anticodón y 5 en el brazo ribotimidina-pseudouridina-citosina (TøC. El tamaño de las lupas correspondió a 5 nucleótidos en la DHU, 7 en la anticodón, 4 en la variable y 7 en la TøC. Lu. columbiana se distingue del resto de especies de Lutzomyia y Phlebotomus secuenciadas a la fecha por la presencia de una guanina en la posición nucleotídica 64, que produce un apareamiento no canónico tipo uracilo-guanina en el brazo aceptor. Se necesitan más estudios para confirmar la utilidad del ARNtSer como marcador molecular para la discriminación de especies de flebotomíneos.The sand fly Lutzomyia columbiana is considered a suspected vector of Leishmania mexicana and Leishmania braziliensis in Colombia. Lu. columbiana belongs to the Lutzomyia verrucarum species group, which included some sibling species. This has motivated the search for molecular markers to distinguish these taxa. In this paper, we described for the first time the

  6. Biologically based multistage modeling of radiation effects

    Energy Technology Data Exchange (ETDEWEB)

    William Hazelton; Suresh Moolgavkar; E. Georg Luebeck

    2005-08-30

    This past year we have made substantial progress in modeling the contribution of homeostatic regulation to low-dose radiation effects and carcinogenesis. We have worked to refine and apply our multistage carcinogenesis models to explicitly incorporate cell cycle states, simple and complex damage, checkpoint delay, slow and fast repair, differentiation, and apoptosis to study the effects of low-dose ionizing radiation in mouse intestinal crypts, as well as in other tissues. We have one paper accepted for publication in ''Advances in Space Research'', and another manuscript in preparation describing this work. I also wrote a chapter describing our combined cell-cycle and multistage carcinogenesis model that will be published in a book on stochastic carcinogenesis models edited by Wei-Yuan Tan. In addition, we organized and held a workshop on ''Biologically Based Modeling of Human Health Effects of Low dose Ionizing Radiation'', July 28-29, 2005 at Fred Hutchinson Cancer Research Center in Seattle, Washington. We had over 20 participants, including Mary Helen Barcellos-Hoff as keynote speaker, talks by most of the low-dose modelers in the DOE low-dose program, experimentalists including Les Redpath (and Mary Helen), Noelle Metting from DOE, and Tony Brooks. It appears that homeostatic regulation may be central to understanding low-dose radiation phenomena. The primary effects of ionizing radiation (IR) are cell killing, delayed cell cycling, and induction of mutations. However, homeostatic regulation causes cells that are killed or damaged by IR to eventually be replaced. Cells with an initiating mutation may have a replacement advantage, leading to clonal expansion of these initiated cells. Thus we have focused particularly on modeling effects that disturb homeostatic regulation as early steps in the carcinogenic process. There are two primary considerations that support our focus on homeostatic regulation. First, a number of

  7. Multistage switched inductor boost converter for renewable energy application

    DEFF Research Database (Denmark)

    Maroti, Pandav Kiran; Padmanaban, Sanjeevikumar; Bhaskar, Mahajan Sagar

    2017-01-01

    In this paper Multistage Switched Inductor Boost Converter (Multistage SIBC) is uttered for renewable energy applications. The projected converter is derived from an amalgamation of the conventional step-up converter and inductor stack. The number of inductor and duty ratio decides the overall...

  8. Exposure Control Using Adaptive Multi-Stage Item Bundles.

    Science.gov (United States)

    Luecht, Richard M.

    This paper presents a multistage adaptive testing test development paradigm that promises to handle content balancing and other test development needs, psychometric reliability concerns, and item exposure. The bundled multistage adaptive testing (BMAT) framework is a modification of the computer-adaptive sequential testing framework introduced by…

  9. 40 CFR 600.316-78 - Multistage manufacture.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Multistage manufacture. 600.316-78 Section 600.316-78 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) ENERGY POLICY... and Later Model Year Automobiles-Labeling § 600.316-78 Multistage manufacture. Where more than one...

  10. Multistage centrifugal extractor of E92 model

    International Nuclear Information System (INIS)

    Wang Houheng; Xing Zhifu; Liu Xiangyan; Liu Shi; Wan Yi; Liang Kui; Hu Benyue

    1987-01-01

    The E92 Model multistage centrifugal extractor has been developed for the recovery of uranium and plutonium from spent nuclear reactor fuel. It offers the following advantages: shorter residence time, low hlod-up, less space required, and simplified startup and shutdown procedures, etc. Experiments on performaces of hydraulics, mass-transfer and crud discharging have proved that this unit provides a wide range of operation. The total flow rate can very from 300 to 450 L/h at organic to aqueous flow ratio of 1 to 5. The unit is designed for ratio of oranic to aqueous phase densities at a range of 0.75 to 0.85. Overall extraction and back-extraction efficiencies which is great than 99.99% were achieved using natural uranium as feed. Experiments showed that mechanical assembling and disassembling of the unit could be rapidly carried out. A run continuning up to 500 hours was stable

  11. Sequencing Cyclic Peptides by Multistage Mass Spectrometry

    Science.gov (United States)

    Mohimani, Hosein; Yang, Yu-Liang; Liu, Wei-Ting; Hsieh, Pei-Wen; Dorrestein, Pieter C.; Pevzner, Pavel A.

    2012-01-01

    Some of the most effective antibiotics (e.g., Vancomycin and Daptomycin) are cyclic peptides produced by non-ribosomal biosynthetic pathways. While hundreds of biomedically important cyclic peptides have been sequenced, the computational techniques for sequencing cyclic peptides are still in their infancy. Previous methods for sequencing peptide antibiotics and other cyclic peptides are based on Nuclear Magnetic Resonance spectroscopy, and require large amount (miligrams) of purified materials that, for most compounds, are not possible to obtain. Recently, development of mass spectrometry based methods has provided some hope for accurate sequencing of cyclic peptides using picograms of materials. In this paper we develop a method for sequencing of cyclic peptides by multistage mass spectrometry, and show its advantages over single stage mass spectrometry. The method is tested on known and new cyclic peptides from Bacillus brevis, Dianthus superbus and Streptomyces griseus, as well as a new family of cyclic peptides produced by marine bacteria. PMID:21751357

  12. Feasibility of Ericsson type isothermal expansion/compression gas turbine cycle for nuclear energy use

    International Nuclear Information System (INIS)

    Shimizu, Akihiko

    2007-01-01

    A gas turbine with potential demand for the next generation nuclear energy use such as HTGR power plants, a gas cooled FBR, a gas cooled nuclear fusion reactor uses helium as working gas and with a closed cycle. Materials constituting a cycle must be set lower than allowable temperature in terms of mechanical strength and radioactivity containment performance and so expansion inlet temperature is remarkably limited. For thermal efficiency improvement, isothermal expansion/isothermal compression Ericsson type gas turbine cycle should be developed using wet surface of an expansion/compressor casing and a duct between stators without depending on an outside heat exchanger performing multistage re-heat/multistage intermediate cooling. Feasibility of an Ericsson cycle in comparison with a Brayton cycle and multi-stage compression/expansion cycle was studied and technologies to be developed were clarified. (author)

  13. Characterization of a solid deuterium converter for ultra-cold neutrons (UCN) in the framework of the Mini-D{sub 2} project at the FRM-II reactor in Munich

    Energy Technology Data Exchange (ETDEWEB)

    Tortorella, D.

    2007-02-07

    Spontaneous breaking of fundamental symmetries is an attractive topic in modern particles physic. Understanding qualitative and quantitative the parameters involved in these kind of processes could help to explain the unbalanced presence in the universe of matter (baryons) with respect to antimatter (anti-baryons). Due to their intrinsic properties, ultra cold neutrons (UCN) are excellent candidates in experiments measuring with high level of accuracy parameters like the electric dipole moment (EDM), the axial-vector coupling constant (g{sub A}), the neutron lifetime ({tau}{sub n}) or in search of quantum effect of gravity. In this work are presented several contributions in the framework of the Mini-D2 project, an innovative strong UCN source under construction at the FRM-II reactor in Munich. An important component of this facility, the solid deuterium UCN converter, is one subject of the thesis. (orig.)

  14. Characterization of a solid deuterium converter for ultra-cold neutrons (UCN) in the framework of the Mini-D2 project at the FRM-II reactor in Munich

    International Nuclear Information System (INIS)

    Tortorella, D.

    2007-01-01

    Spontaneous breaking of fundamental symmetries is an attractive topic in modern particles physic. Understanding qualitative and quantitative the parameters involved in these kind of processes could help to explain the unbalanced presence in the universe of matter (baryons) with respect to antimatter (anti-baryons). Due to their intrinsic properties, ultra cold neutrons (UCN) are excellent candidates in experiments measuring with high level of accuracy parameters like the electric dipole moment (EDM), the axial-vector coupling constant (g A ), the neutron lifetime (τ n ) or in search of quantum effect of gravity. In this work are presented several contributions in the framework of the Mini-D2 project, an innovative strong UCN source under construction at the FRM-II reactor in Munich. An important component of this facility, the solid deuterium UCN converter, is one subject of the thesis. (orig.)

  15. Axial Turbine Aerodynamic Design of Small Heavy-Duty Gas Turbines

    International Nuclear Information System (INIS)

    Kim, Joung Seok; Lee, Wu Sang; Ryu, Je Wook

    2013-01-01

    This study describes the aerodynamic design procedure for the axial turbines of a small heavy-duty gas turbine engine being developed by Docosan Heavy Industries. The design procedure mainly consists of three parts: namely, flow path design, airfoil design, and 3a performance calculation. To design the optimized flow path, through flow calculations as well as the loss estimation are widely used to evaluate the effect of geometric variables, for example, shape of meridional plane, mean radius, blades axial gap, and had angle. During the airfoil design procedure, the optimum number of blades is calculated by empirical correlations based on the in/outlet flow angles, and then 2a airfoil planar sections are designed carefully, followed by 2a B2 NS calculations. The designed planar sections are stacked along the span wise direction, leading to a 3a surfaced airfoil shape. To consider the 3a effect on turbine performance, 3a multistage Euler calculation, single row, and multistage NS calculations are performed

  16. Study on hydrodynamics and mass transfer of the critically safe multistage mixer-settler

    International Nuclear Information System (INIS)

    Zhang Weibo; Jiao Rongzhou; Liu Bingren

    1992-08-01

    The study on structure of critically safe multistage mixer-settler for the extraction process of high enriched uranium and plutonium has been completed. The mixer-settler has simple structure, good critical safety, flexibility in operation (O/A from 0.5 to 5) and high extraction efficiency (E x > 90%). These performances have been proved in the hydrodynamics and mass transfer experiments at a three stages cascade mixer-settler. Based on the others experience, a trapezoidal impeller combined with half-open turbine is developed which has stronger pumping and well mixing function at low rotating speed. The optimal rotating speed is 250 to 280 r/min obtained by experiments

  17. Hydraulic turbines and auxiliary equipment

    Energy Technology Data Exchange (ETDEWEB)

    Luo Gaorong [Organization of the United Nations, Beijing (China). International Centre of Small Hydroelectric Power Plants

    1995-07-01

    This document presents a general overview on hydraulic turbines and auxiliary equipment, emphasizing the turbine classification, in accordance with the different types of turbines, standard turbine series in China, turbine selection based on the basic data required for the preliminary design, general hill model curves, chart of turbine series and the arrangement of application for hydraulic turbines, hydraulic turbine testing, and speed regulating device.

  18. Turbine stage model

    International Nuclear Information System (INIS)

    Kazantsev, A.A.

    2009-01-01

    A model of turbine stage for calculations of NPP turbine department dynamics in real time was developed. The simulation results were compared with manufacturer calculations for NPP low-speed and fast turbines. The comparison results have shown that the model is valid for real time simulation of all modes of turbines operation. The model allows calculating turbine stage parameters with 1% accuracy. It was shown that the developed turbine stage model meets the accuracy requirements if the data of turbine blades setting angles for all turbine stages are available [ru

  19. Aerodynamics and flow characterisation of multistage rockets

    Science.gov (United States)

    Srinivas, G.; Prakash, M. V. S.

    2017-05-01

    The main objective of this paper is to conduct a systematic flow analysis on single, double and multistage rockets using ANSYS software. Today non-air breathing propulsion is increasing dramatically for the enhancement of space exploration. The rocket propulsion is playing vital role in carrying the payload to the destination. Day to day rocket aerodynamic performance and flow characterization analysis has becoming challenging task to the researchers. Taking this task as motivation a systematic literature is conducted to achieve better aerodynamic and flow characterization on various rocket models. The analyses on rocket models are very little especially in numerical side and experimental area. Each rocket stage analysis conducted for different Mach numbers and having different flow varying angle of attacks for finding the critical efficiency performance parameters like pressure, density and velocity. After successful completion of the analysis the research reveals that flow around the rocket body for Mach number 4 and 5 best suitable for designed payload. Another major objective of this paper is to bring best aerodynamics flow characterizations in both aero and mechanical features. This paper also brings feature prospectus of rocket stage technology in the field of aerodynamic design.

  20. Simulations of multistage intense ion beam acceleration

    International Nuclear Information System (INIS)

    Slutz, S.A.; Poukey, J.W.

    1992-01-01

    An analytic theory for magnetically insulated, multistage acceleration of high intensity ion beams, where the diamagnetic effect due to electron flow is important, has been presented by Slutz and Desjarlais. The theory predicts the existence of two limiting voltages called V 1 (W) and V 2 (W), which are both functions of the injection energy qW of ions entering the accelerating gap. As the voltage approaches V 1 (W), unlimited beam-current density can penetrate the gap without the formation of a virtual anode because the dynamic gap goes to zero. Unlimited beam current density can penetrate an accelerating gap above V 2 (W), although a virtual anode is formed. It was found that the behavior of these limiting voltages is strongly dependent on the electron density profile. The authors have investigated the behavior of these limiting voltages numerically using the 2-D particle-in-cell (PIC) code MAGIC. Results of these simulations are consistent with the superinsulated analytic results. This is not surprising, since the ignored coordinate eliminates instabilities known to be important from studies of single stage magnetically insulated ion diodes. To investigate the effect of these instabilities the authors have simulated the problem with the 3-D PIC code QUICKSILVER, which indicates behavior that is consistent with the saturated model

  1. Unsteady Aerodynamics & Aeromechanics of Multi-Stage Turbomachinery Blading

    National Research Council Canada - National Science Library

    Fleeter, Sanford

    2002-01-01

    .... A benchmark-standard multistage transonic research compressor was developed by modifying the Purdue High-Speed Axial Compressor to feature new IGV and stator rows representative of modern high pressure compressors...

  2. Some design aspects of multistage flash distillation process

    International Nuclear Information System (INIS)

    Ahmad, Mohammad.

    1975-01-01

    The purpose of this paper is to examine the effect of the design variables of multistage flash (MSF) process on the performance and/or the cost of the desalting plant, and to establish certain design trends

  3. UCN gravitational spectrometer

    International Nuclear Information System (INIS)

    Kawabata, Yuji

    1988-01-01

    Concept design is carried out of two types of ultra cold neutron scallering equipment using the fall-focusing principle. One of the systems comprises a vertical gravitational spectrometer and the other includes a horizontal gravitation analyzer. A study is made of their performance and the following results are obtained. Fall-focusing type ultra cold neutron scattering equipment can achieve a high accuracy for measurement of energy and momentum. Compared with conventional neutron scattering systems, this type of equipment can use neutron very efficiently because scattered neutrons within a larger solid angle can be used. The maximum solid angle is nearly 4π and 2π for the vertical and horizontal type, respectively. Another feature is that the size of equipment can be reduced. In the present concept design, the equipment is spherical with a diameter of about 1 m, as compared with NESSIE which is 6.7 m in length and 4.85 m in height with about the same accuracy. Two horizontal analyzers and a vertical spectroscope are proposed. They are suitable for angle-dependent non-elastic scattering in the neutron velocity range of 6∼15 m/s, pure elastic scattering in the range of 4∼7 m/s, or angle-integration non-elastic scattering in the range of 4∼15 m/s. (N.K.)

  4. Turbine main engines

    CERN Document Server

    Main, John B; Herbert, C W; Bennett, A J S

    1965-01-01

    Turbine Main Engines deals with the principle of operation of turbine main engines. Topics covered include practical considerations that affect turbine design and efficiency; steam turbine rotors, blades, nozzles, and diaphragms; lubricating oil systems; and gas turbines for use with nuclear reactors. Gas turbines for naval boost propulsion, merchant ship propulsion, and naval main propulsion are also considered. This book is divided into three parts and begins with an overview of the basic mode of operation of the steam turbine engine and how it converts the pressure energy of the ingoing ste

  5. Turbine system and adapter

    Science.gov (United States)

    Hogberg, Nicholas Alvin; Garcia-Crespo, Andres Jose

    2017-05-30

    A turbine system and adapter are disclosed. The adapter includes a turbine attachment portion having a first geometry arranged to receive a corresponding geometry of a wheelpost of a turbine rotor, and a bucket attachment portion having a second geometry arranged to receive a corresponding geometry of a root portion of a non-metallic turbine bucket. Another adapter includes a turbine attachment portion arranged to receive a plurality of wheelposts of a turbine rotor, and a bucket attachment portion arranged to receive a plurality of non-metallic turbine buckets having single dovetail configuration root portions. The turbine system includes a turbine rotor wheel configured to receive metal buckets, at least one adapter secured to at least one wheelpost on the turbine rotor wheel, and at least one non-metallic bucket secured to the at least one adapter.

  6. HIGH EFFICIENCY TURBINE

    OpenAIRE

    VARMA, VIJAYA KRUSHNA

    2012-01-01

    Varma designed ultra modern and high efficiency turbines which can use gas, steam or fuels as feed to produce electricity or mechanical work for wide range of usages and applications in industries or at work sites. Varma turbine engines can be used in all types of vehicles. These turbines can also be used in aircraft, ships, battle tanks, dredgers, mining equipment, earth moving machines etc, Salient features of Varma Turbines. 1. Varma turbines are simple in design, easy to manufac...

  7. Turbine maintenance and modernization

    Energy Technology Data Exchange (ETDEWEB)

    Unga, E. [Teollisuuden Voima Oy, Olkiluoto (Finland)

    1998-12-31

    The disturbance-free operation of the turbine plant plays an important role in reaching good production results. In the turbine maintenance of the Olkiluoto nuclear power plant the lifetime and efficiency of turbine components and the lifetime costs are taken into account in determining the turbine maintenance and modernization/improvement program. The turbine maintenance program and improvement/modernization measures taken in the plant units are described in this presentation. (orig.)

  8. Turbine maintenance and modernization

    Energy Technology Data Exchange (ETDEWEB)

    Unga, E [Teollisuuden Voima Oy, Olkiluoto (Finland)

    1999-12-31

    The disturbance-free operation of the turbine plant plays an important role in reaching good production results. In the turbine maintenance of the Olkiluoto nuclear power plant the lifetime and efficiency of turbine components and the lifetime costs are taken into account in determining the turbine maintenance and modernization/improvement program. The turbine maintenance program and improvement/modernization measures taken in the plant units are described in this presentation. (orig.)

  9. Combined heat and power plants with parallel tandem steam turbines; Smaaskalig kraftvaerme med parallellkopplade tandemturbiner

    Energy Technology Data Exchange (ETDEWEB)

    Steinwall, Pontus; Norstroem, Urban; Pettersson, Camilla; Oesterlin, Erik

    2004-12-01

    We investigate the technical and economical conditions for a concept with parallel coupled tandem turbines in small scale combined heat and power plants fired with bio-fuel and waste. Performance and heat production costs at varying electricity prices for the concept with two smaller tandem coupled steam turbines has been compared to the traditional concept with one single multi-staged turbine. Three different types of plants have been investigated: - Bio fuelled CHP plant with thermal capacity of 15 MW{sub th}; - Waste fired CHP plant with thermal capacity of 20 MW{sub th}; - Bio fuelled CHP plant with thermal capacity of 25 MW{sub th}. The simple steam turbines (Curtis turbines) used in the tandem arrangement has an isentropic efficiency of about 49 to 53% compared to the multi-staged steam turbines with isentropic efficiency in the range of 59% to 81%. The lower isentropic efficiency for the single staged turbines is to some extent compensated at partial load when one of the two turbines can be shut down leading to better operational conditions for the one still in operation. For concepts with saturated steam at partial load below 50% the tandem arrangements presents higher electricity efficiency than the conventional single turbine alternative. The difference in annual production of electricity is therefore less than the difference in isentropic efficiency for the two concepts. Production of electricity is between 2% and 42% lower for the tandem arrangements in this study. Investment costs for the turbine island has been calculated for the two turbine concepts and when the costs for turbines, generator, power transmission, condensing system, piping system, buildings, assembling, commissioning and engineering has been added the sum is about the same for the two concepts. For the bio-fuelled plant with thermal capacity of 15 MW{sub th} the turbine island amount to about 10-12 MSEK and about 13-15 MSEK for the waste fired plant with a thermal capacity of 20 MW

  10. Multistage Magnetic Separator of Cells and Proteins

    Science.gov (United States)

    Barton, Ken; Ainsworth, Mark; Daily, Bruce; Dunn, Scott; Metz, Bill; Vellinger, John; Taylor, Brock; Meador, Bruce

    2005-01-01

    The multistage electromagnetic separator for purifying cells and magnetic particles (MAGSEP) is a laboratory apparatus for separating and/or purifying particles (especially biological cells) on the basis of their magnetic susceptibility and magnetophoretic mobility. Whereas a typical prior apparatus based on similar principles offers only a single stage of separation, the MAGSEP, as its full name indicates, offers multiple stages of separation; this makes it possible to refine a sample population of particles to a higher level of purity or to categorize multiple portions of the sample on the basis of magnetic susceptibility and/or magnetophoretic mobility. The MAGSEP includes a processing unit and an electronic unit coupled to a personal computer. The processing unit includes upper and lower plates, a plate-rotation system, an electromagnet, an electromagnet-translation system, and a capture-magnet assembly. The plates are bolted together through a roller bearing that allows the plates to rotate with respect to each other. An interface between the plates acts as a seal for separating fluids. A lower cuvette can be aligned with as many as 15 upper cuvette stations for fraction collection during processing. A two-phase stepping motor drives the rotation system, causing the upper plate to rotate for the collection of each fraction of the sample material. The electromagnet generates a magnetic field across the lower cuvette, while the translation system translates the electromagnet upward along the lower cuvette. The current supplied to the electromagnet, and thus the magnetic flux density at the pole face of the electromagnet, can be set at a programmed value between 0 and 1,400 gauss (0.14 T). The rate of translation can be programmed between 5 and 2,000 m/s so as to align all sample particles in the same position in the cuvette. The capture magnet can be a permanent magnet. It is mounted on an arm connected to a stepping motor. The stepping motor rotates the arm to

  11. Characterization of solid D{sub 2} as a source material for ultra cold neutrons (UCN) and development of a detector concept for the detection of protons from the neutron decay

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Axel Reimer

    2008-12-09

    In the first part of this thesis, properties of the UCN-converter material solid deuterium (sD{sub 2}) are studied. A series of investigations of various sD{sub 2} crystals by means of optical spectroscopy and neutron scattering resulted in: (i) a freezing technique suitable for UCN sources (ii) an efficient method to achieve a high ortho concentration, (iii) a direct way to calculate the UCN production cross-section from the dynamic structure factor S(q, {omega}), (iv) the identification of six excitations responsible for UCN production (v) the interpretation of one excitation at E=12 meV as a multi-phonon process (vi) the discovery of an additional spin-dependent UCN loss mechanism at q=2.1A{sup -1} and E=1.8 meV. A complementary series of experiments was performed at the FRMII, testing the production of UCN with the studied sample preparation after different the characterization mentioned above. Besides establishing a technique for annealing sD{sub 2} crystals to improve the UCN production rate, an additional loss cross section ({sigma}{sub x}=8 barn at 4.5 K indirect proportional to the ortho concentration) was found. Based on these findings, a new conceptual layout of the miniD{sub 2} source was developed. In the second part, the diffuse scattering probability f and the loss probability per wall collision {mu} were measured for differently prepared UCN guides using the storageand the so called two-hole method. Electropolished, rough stainless steel and Al tubes with different coatings at temperature variation and surface conditions were measured. The third part deals with the development of a proton detector for the neutron lifetime experiment PENeLOPE, which is based on gravitational and magnetic UCN storage and counting of the protons from the decay. A concept for a large-area proton detector based on thin scintillation counters operating in cryogenic environment was developed based on simulations and experimental studies. In addition to the characterization

  12. Characterization of solid D2 as a source material for ultra cold neutrons (UCN) and development of a detector concept for the detection of protons from the neutron decay

    International Nuclear Information System (INIS)

    Mueller, Axel Reimer

    2008-01-01

    In the first part of this thesis, properties of the UCN-converter material solid deuterium (sD 2 ) are studied. A series of investigations of various sD 2 crystals by means of optical spectroscopy and neutron scattering resulted in: (i) a freezing technique suitable for UCN sources (ii) an efficient method to achieve a high ortho concentration, (iii) a direct way to calculate the UCN production cross-section from the dynamic structure factor S(q, ω), (iv) the identification of six excitations responsible for UCN production (v) the interpretation of one excitation at E=12 meV as a multi-phonon process (vi) the discovery of an additional spin-dependent UCN loss mechanism at q=2.1A -1 and E=1.8 meV. A complementary series of experiments was performed at the FRMII, testing the production of UCN with the studied sample preparation after different the characterization mentioned above. Besides establishing a technique for annealing sD 2 crystals to improve the UCN production rate, an additional loss cross section (σ x =8 barn at 4.5 K indirect proportional to the ortho concentration) was found. Based on these findings, a new conceptual layout of the miniD 2 source was developed. In the second part, the diffuse scattering probability f and the loss probability per wall collision μ were measured for differently prepared UCN guides using the storageand the so called two-hole method. Electropolished, rough stainless steel and Al tubes with different coatings at temperature variation and surface conditions were measured. The third part deals with the development of a proton detector for the neutron lifetime experiment PENeLOPE, which is based on gravitational and magnetic UCN storage and counting of the protons from the decay. A concept for a large-area proton detector based on thin scintillation counters operating in cryogenic environment was developed based on simulations and experimental studies. In addition to the characterization of CsI(Tl) and CsI scintillators, a

  13. Steam turbine cycle

    International Nuclear Information System (INIS)

    Okuzumi, Naoaki.

    1994-01-01

    In a steam turbine cycle, steams exhausted from the turbine are extracted, and they are connected to a steam sucking pipe of a steam injector, and a discharge pipe of the steam injector is connected to an inlet of a water turbine. High pressure discharge water is obtained from low pressure steams by utilizing a pressurizing performance of the steam injector and the water turbine is rotated by the high pressure water to generate electric power. This recover and reutilize discharged heat of the steam turbine effectively, thereby enabling to improve heat efficiency of the steam turbine cycle. (T.M.)

  14. The swirl turbine

    Science.gov (United States)

    Haluza, M.; Pochylý, F.; Rudolf, P.

    2012-11-01

    In the article is introduced the new type of the turbine - swirl turbine. This turbine is based on opposite principle than Kaplan turbine. Euler equation is satisfied in the form gHηh = -u2vu2. From this equation is seen, that inflow of liquid into the runner is without rotation and on the outflow is a rotation of liquid opposite of rotation of runner. This turbine is suitable for small head and large discharge. Some constructional variants of this turbine are introduced in the article and theoretical aspects regarding losses in the draft tube. The theory is followed by computational simulations in Fluent and experiments using laser Doppler anemometry.

  15. Aerodynamics of Wind Turbines

    DEFF Research Database (Denmark)

    Hansen, Martin Otto Laver

    Aerodynamics of Wind Turbines is the established essential text for the fundamental solutions to efficient wind turbine design. Now in its second edition, it has been entirely updated and substantially extended to reflect advances in technology, research into rotor aerodynamics and the structural...... response of the wind turbine structure. Topics covered include increasing mass flow through the turbine, performance at low and high wind speeds, assessment of the extreme conditions under which the turbine will perform and the theory for calculating the lifetime of the turbine. The classical Blade Element...... Momentum method is also covered, as are eigenmodes and the dynamic behavior of a turbine. The new material includes a description of the effects of the dynamics and how this can be modeled in an aeroelastic code, which is widely used in the design and verification of modern wind turbines. Further...

  16. Aerodynamics of wind turbines

    DEFF Research Database (Denmark)

    Hansen, Martin Otto Laver

    Aerodynamics of Wind Turbines is the established essential text for the fundamental solutions to efficient wind turbine design. Now in its third edition, it has been substantially updated with respect to structural dynamics and control. The new control chapter now includes details on how to design...... Turbines (VAWT). Topics covered include increasing mass flow through the turbine, performance at low and high wind speeds, assessment of the extreme conditions under which the turbine will perform and the theory for calculating the lifetime of the turbine. The classical Blade Element Momentum method...... is also covered, as are eigenmodes and the dynamic behaviour of a turbine. The book describes the effects of the dynamics and how this can be modelled in an aeroelastic code, which is widely used in the design and verification of modern wind turbines. Furthermore, it examines how to calculate...

  17. TurbinAID

    International Nuclear Information System (INIS)

    Moradian, M.A.; Chow, M.P.; Osborne, R.L.; Jenkins, M.A.

    1991-01-01

    The Westinghouse Turbine Artificial Intelligence Diagnostics system or TurbinAID, can diagnose both thermodynamic and mechanical component anomalies within the turbine, and around the turbine cycle. any monitoring system can detect that a variable is in an abnormal state, but TurbinAID can also indicate the cause, and provide recommended corrective action(s). The TurbinAID Expert Systems utilize multiple sensor and variable inputs, and their interdependencies in the generation of a diagnosis. The system performs sensor validation as part of the data acquisition scheme. The TurbinAID system has been in operation for several years. This paper describes the monitoring and diagnostic functions provided by TurbinAID, and how the utility industry both nuclear and fossil, can utilize the system to enhance unit operation

  18. Turbulence and wind turbines

    DEFF Research Database (Denmark)

    Brand, Arno J.; Peinke, Joachim; Mann, Jakob

    2011-01-01

    The nature of turbulent flow towards, near and behind a wind turbine, the effect of turbulence on the electricity production and the mechanical loading of individual and clustered wind turbines, and some future issues are discussed.......The nature of turbulent flow towards, near and behind a wind turbine, the effect of turbulence on the electricity production and the mechanical loading of individual and clustered wind turbines, and some future issues are discussed....

  19. 10 MW Supercritical CO2 Turbine Test

    Energy Technology Data Exchange (ETDEWEB)

    Turchi, Craig

    2014-01-29

    The Supercritical CO2 Turbine Test project was to demonstrate the inherent efficiencies of a supercritical carbon dioxide (s-CO2) power turbine and associated turbomachinery under conditions and at a scale relevant to commercial concentrating solar power (CSP) projects, thereby accelerating the commercial deployment of this new power generation technology. The project involved eight partnering organizations: NREL, Sandia National Laboratories, Echogen Power Systems, Abengoa Solar, University of Wisconsin at Madison, Electric Power Research Institute, Barber-Nichols, and the CSP Program of the U.S. Department of Energy. The multi-year project planned to design, fabricate, and validate an s-CO2 power turbine of nominally 10 MWe that is capable of operation at up to 700°C and operates in a dry-cooled test loop. The project plan consisted of three phases: (1) system design and modeling, (2) fabrication, and (3) testing. The major accomplishments of Phase 1 included: Design of a multistage, axial-flow, s-CO2 power turbine; Design modifications to an existing turbocompressor to provide s-CO2 flow for the test system; Updated equipment and installation costs for the turbomachinery and associated support infrastructure; Development of simulation tools for the test loop itself and for more efficient cycle designs that are of greater commercial interest; Simulation of s-CO2 power cycle integration into molten-nitrate-salt CSP systems indicating a cost benefit of up to 8% in levelized cost of energy; Identification of recuperator cost as a key economic parameter; Corrosion data for multiple alloys at temperatures up to 650ºC in high-pressure CO2 and recommendations for materials-of-construction; and Revised test plan and preliminary operating conditions based on the ongoing tests of related equipment. Phase 1 established that the cost of the facility needed to test the power turbine at its full power and temperature would exceed the planned funding for Phases 2 and 3. Late

  20. Sliding vane geometry turbines

    Science.gov (United States)

    Sun, Harold Huimin; Zhang, Jizhong; Hu, Liangjun; Hanna, Dave R

    2014-12-30

    Various systems and methods are described for a variable geometry turbine. In one example, a turbine nozzle comprises a central axis and a nozzle vane. The nozzle vane includes a stationary vane and a sliding vane. The sliding vane is positioned to slide in a direction substantially tangent to an inner circumference of the turbine nozzle and in contact with the stationary vane.

  1. Development and validation of a full-range performance analysis model for a three-spool gas turbine with turbine cooling

    International Nuclear Information System (INIS)

    Song, Yin; Gu, Chun-wei; Ji, Xing-xing

    2015-01-01

    The performance analysis of a gas turbine is important for both its design and its operation. For modern gas turbines, the cooling flow introduces a noteworthy thermodynamic loss; thus, the determination of the cooling flow rate will clearly influence the accuracy of performance calculations. In this paper, a full-range performance analysis model is established for a three-spool gas turbine with an open-circuit convective blade cooling system. A hybrid turbine cooling model is embedded in the analysis to predict the amount of cooling air accurately and thus to remove the errors induced by the relatively arbitrary value of cooling air requirements in the previous research. The model is subsequently used to calculate the gas turbine performance; the calculation results are validated with detailed test data. Furthermore, multistage conjugate heat transfer analysis is performed for the turbine section. The results indicate that with the same coolant condition and flow rate as those in the performance analysis, the blade metal has been effectively cooled; in addition, the maximum temperature predicted by conjugate heat transfer analysis is close to the corresponding value in the cooling model. Hence, the present model provides an effective tool for analyzing the performance of a gas turbine with cooling. - Highlights: • We established a performance model for a gas turbine with convective cooling. • A hybrid turbine cooling model is embedded in the performance analysis. • The accuracy of the model is validated with detailed test data of the gas turbine. • Conjugate heat transfer analysis is performed for the turbine for verification

  2. Demand management in Multi-Stage Distribution Chain

    NARCIS (Netherlands)

    de Kok, T.; Janssen, F.B.S.L.P.

    1996-01-01

    In this paper we discuss demand management problems in a multi-stage distribution chain.We focus on distribution chains where demand processes have high variability due to a few large customer orders.We give a possible explanation, and suggest two simple procedures that help to smooth demand.It is

  3. Bio-inspired approach to multistage image processing

    Science.gov (United States)

    Timchenko, Leonid I.; Pavlov, Sergii V.; Kokryatskaya, Natalia I.; Poplavska, Anna A.; Kobylyanska, Iryna M.; Burdenyuk, Iryna I.; Wójcik, Waldemar; Uvaysova, Svetlana; Orazbekov, Zhassulan; Kashaganova, Gulzhan

    2017-08-01

    Multistage integration of visual information in the brain allows people to respond quickly to most significant stimuli while preserving the ability to recognize small details in the image. Implementation of this principle in technical systems can lead to more efficient processing procedures. The multistage approach to image processing, described in this paper, comprises main types of cortical multistage convergence. One of these types occurs within each visual pathway and the other between the pathways. This approach maps input images into a flexible hierarchy which reflects the complexity of the image data. The procedures of temporal image decomposition and hierarchy formation are described in mathematical terms. The multistage system highlights spatial regularities, which are passed through a number of transformational levels to generate a coded representation of the image which encapsulates, in a computer manner, structure on different hierarchical levels in the image. At each processing stage a single output result is computed to allow a very quick response from the system. The result is represented as an activity pattern, which can be compared with previously computed patterns on the basis of the closest match.

  4. Test Information Targeting Strategies for Adaptive Multistage Testing Designs.

    Science.gov (United States)

    Luecht, Richard M.; Burgin, William

    Adaptive multistage testlet (MST) designs appear to be gaining popularity for many large-scale computer-based testing programs. These adaptive MST designs use a modularized configuration of preconstructed testlets and embedded score-routing schemes to prepackage different forms of an adaptive test. The conditional information targeting (CIT)…

  5. Information Overload in Multi-Stage Selection Procedures

    NARCIS (Netherlands)

    S.S. Ficco (Stefano); V.A. Karamychev (Vladimir)

    2004-01-01

    textabstractThe paper studies information processing imperfections in a fully rational decision-making network. It is shown that imperfect information transmission and imperfect information acquisition in a multi-stage selection game yield information overload. The paper analyses the mechanisms

  6. Optimal testlet pool assembly for multistage testing designs

    NARCIS (Netherlands)

    Ariel, A.; Veldkamp, Bernard P.; Breithaupt, Krista

    2006-01-01

    Computerized multistage testing (MST) designs require sets of test questions (testlets) to be assembled to meet strict, often competing criteria. Rules that govern testlet assembly may dictate the number of questions on a particular subject or may describe desirable statistical properties for the

  7. Analysis of multi-stage open shop processing systems

    NARCIS (Netherlands)

    Eggermont, C.E.J.; Schrijver, A.; Woeginger, G.J.; Schwentick, T.; Dürr, C.

    2011-01-01

    We study algorithmic problems in multi-stage open shop processing systems that are centered around reachability and deadlock detection questions. We characterize safe and unsafe system states. We show that it is easy to recognize system states that can be reached from the initial state (where the

  8. Turbine Imaging Technology Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Moursund, Russell A.; Carlson, Thomas J.

    2004-12-31

    The goal of this project was to identify and evaluate imaging alternatives for observing the behavior of juvenile fish within an operating Kaplan turbine unit with a focus on methods to quantify fish injury mechanisms inside an operating turbine unit. Imaging methods are particularly needed to observe the approach and interaction of fish with turbine structural elements. This evaluation documents both the opportunities and constraints for observing juvenile fish at specific locations during turbine passage. The information may be used to acquire the scientific knowledge to make structural improvements and create opportunities for industry to modify turbines and improve fish passage conditions.

  9. Turbine related fish mortality

    International Nuclear Information System (INIS)

    Eicher, G.J.

    1993-01-01

    A literature review was conducted to assess the factors affecting turbine-related fish mortality. The mechanics of fish passage through a turbine is outlined, and various turbine related stresses are described, including pressure and shear effects, hydraulic head, turbine efficiency, and tailwater level. The methodologies used in determining the effects of fish passage are evaluated. The necessity of adequate controls in each test is noted. It is concluded that mortality is the result of several factors such as hardiness of study fish, fish size, concentrations of dissolved gases, and amounts of cavitation. Comparisons between Francis and Kaplan turbines indicate little difference in percent mortality. 27 refs., 5 figs

  10. Turbine Imaging Technology Assessment

    International Nuclear Information System (INIS)

    Moursund, Russell A.; Carlson, Thomas J.

    2004-01-01

    The goal of this project was to identify and evaluate imaging alternatives for observing the behavior of juvenile fish within an operating Kaplan turbine unit with a focus on methods to quantify fish injury mechanisms inside an operating turbine unit. Imaging methods are particularly needed to observe the approach and interaction of fish with turbine structural elements. This evaluation documents both the opportunities and constraints for observing juvenile fish at specific locations during turbine passage. The information may be used to acquire the scientific knowledge to make structural improvements and create opportunities for industry to modify turbines and improve fish passage conditions

  11. Micro-turbines

    International Nuclear Information System (INIS)

    Tashevski, Done

    2003-01-01

    In this paper a principle of micro-turbines operation, type of micro-turbines and their characteristics is presented. It is shown their usage in cogeneration and three generation application with the characteristics, the influence of more factors on micro-turbines operation as well as the possibility for application in Macedonia. The paper is result of the author's participation in the training program 'Micro-turbine technology' in Florida, USA. The characteristics of different types micro-turbines by several world producers are shown, with accent on US micro-turbines producers (Capstone, Elliott). By using the gathered Author's knowledge, contacts and the previous knowledge, conclusions and recommendations for implementation of micro-turbines in Macedonia are given. (Author)

  12. Optimizing Parameters of Axial Pressure-Compounded Ultra-Low Power Impulse Turbines at Preliminary Design

    Science.gov (United States)

    Kalabukhov, D. S.; Radko, V. M.; Grigoriev, V. A.

    2018-01-01

    Ultra-low power turbine drives are used as energy sources in auxiliary power systems, energy units, terrestrial, marine, air and space transport within the confines of shaft power N td = 0.01…10 kW. In this paper we propose a new approach to the development of surrogate models for evaluating the integrated efficiency of multistage ultra-low power impulse turbine with pressure stages. This method is based on the use of existing mathematical models of ultra-low power turbine stage efficiency and mass. It has been used in a method for selecting the rational parameters of two-stage axial ultra-low power turbine. The article describes the basic features of an algorithm for two-stage turbine parameters optimization and for efficiency criteria evaluating. Pledged mathematical models are intended for use at the preliminary design of turbine drive. The optimization method was tested at preliminary design of an air starter turbine. Validation was carried out by comparing the results of optimization calculations and numerical gas-dynamic simulation in the Ansys CFX package. The results indicate a sufficient accuracy of used surrogate models for axial two-stage turbine parameters selection

  13. Multi-stage decoding of multi-level modulation codes

    Science.gov (United States)

    Lin, Shu; Kasami, Tadao; Costello, Daniel J., Jr.

    1991-01-01

    Various types of multi-stage decoding for multi-level modulation codes are investigated. It is shown that if the component codes of a multi-level modulation code and types of decoding at various stages are chosen properly, high spectral efficiency and large coding gain can be achieved with reduced decoding complexity. Particularly, it is shown that the difference in performance between the suboptimum multi-stage soft-decision maximum likelihood decoding of a modulation code and the single-stage optimum soft-decision decoding of the code is very small, only a fraction of dB loss in signal to noise ratio at a bit error rate (BER) of 10(exp -6).

  14. Fuzzy-like multiple objective multistage decision making

    CERN Document Server

    Xu, Jiuping

    2014-01-01

    Decision has inspired reflection of many thinkers since the ancient times. With the rapid development of science and society, appropriate dynamic decision making has been playing an increasingly important role in many areas of human activity including engineering, management, economy and others. In most real-world problems, decision makers usually have to make decisions sequentially at different points in time and space, at different levels for a component or a system, while facing multiple and conflicting objectives and a hybrid uncertain environment where fuzziness and randomness co-exist in a decision making process. This leads to the development of fuzzy-like multiple objective multistage decision making. This book provides a thorough understanding of the concepts of dynamic optimization from a modern perspective and presents the state-of-the-art methodology for modeling, analyzing and solving the most typical multiple objective multistage decision making practical application problems under fuzzy-like un...

  15. Various multistage ensembles for prediction of heating energy consumption

    Directory of Open Access Journals (Sweden)

    Radisa Jovanovic

    2015-04-01

    Full Text Available Feedforward neural network models are created for prediction of daily heating energy consumption of a NTNU university campus Gloshaugen using actual measured data for training and testing. Improvement of prediction accuracy is proposed by using neural network ensemble. Previously trained feed-forward neural networks are first separated into clusters, using k-means algorithm, and then the best network of each cluster is chosen as member of an ensemble. Two conventional averaging methods for obtaining ensemble output are applied; simple and weighted. In order to achieve better prediction results, multistage ensemble is investigated. As second level, adaptive neuro-fuzzy inference system with various clustering and membership functions are used to aggregate the selected ensemble members. Feedforward neural network in second stage is also analyzed. It is shown that using ensemble of neural networks can predict heating energy consumption with better accuracy than the best trained single neural network, while the best results are achieved with multistage ensemble.

  16. Performance prediction method for a multi-stage Knudsen pump

    Science.gov (United States)

    Kugimoto, K.; Hirota, Y.; Kizaki, Y.; Yamaguchi, H.; Niimi, T.

    2017-12-01

    In this study, the novel method to predict the performance of a multi-stage Knudsen pump is proposed. The performance prediction method is carried out in two steps numerically with the assistance of a simple experimental result. In the first step, the performance of a single-stage Knudsen pump was measured experimentally under various pressure conditions, and the relationship of the mass flow rate was obtained with respect to the average pressure between the inlet and outlet of the pump and the pressure difference between them. In the second step, the performance of a multi-stage pump was analyzed by a one-dimensional model derived from the mass conservation law. The performances predicted by the 1D-model of 1-stage, 2-stage, 3-stage, and 4-stage pumps were validated by the experimental results for the corresponding number of stages. It was concluded that the proposed prediction method works properly.

  17. Multi-Stage Transportation Problem With Capacity Limit

    Directory of Open Access Journals (Sweden)

    I. Brezina

    2010-06-01

    Full Text Available The classical transportation problem can be applied in a more general way in practice. Related problems as Multi-commodity transportation problem, Transportation problems with different kind of vehicles, Multi-stage transportation problems, Transportation problem with capacity limit is an extension of the classical transportation problem considering the additional special condition. For solving such problems many optimization techniques (dynamic programming, linear programming, special algorithms for transportation problem etc. and heuristics approaches (e.g. evolutionary techniques were developed. This article considers Multi-stage transportation problem with capacity limit that reflects limits of transported materials (commodity quantity. Discussed issues are: theoretical base, problem formulation as way as new proposed algorithm for that problem.

  18. Wind turbine operated sailboat

    Energy Technology Data Exchange (ETDEWEB)

    Hall, R.

    1990-07-31

    A wind powered boat is disclosed which incorporates a vertical axis rotary turbine. A shaft portion extends downwardly from the turbine to a water pump, with the boat being provided with a forwardly opening inlet and a rearwardly opening outlet from the water pump. When rotating, the turbine operates the pump by the shaft to draw in water through the inlet, thereby creating a low pressure area in front of the boat, and to force the water out through the outlet for propelling the boat. In a preferred embodiment, the boat has a catamaran construction or is a large ocean going vessel with enough width to provide a buffer to either side of the turbine, and the turbine is the Darrieus rotor type. The pump is a standard centrifugal type of pump. A self adjusting braking device for the turbine is also disclosed, which prevents over-rotation and is also capable of storing heat energy generated during braking. 4 figs.

  19. The swirl turbine

    International Nuclear Information System (INIS)

    Haluza, M; Pochylý, F; Rudolf, P

    2012-01-01

    In the article is introduced the new type of the turbine - swirl turbine. This turbine is based on opposite principle than Kaplan turbine. Euler equation is satisfied in the form gHη h = −u 2 v u2 . From this equation is seen, that inflow of liquid into the runner is without rotation and on the outflow is a rotation of liquid opposite of rotation of runner. This turbine is suitable for small head and large discharge. Some constructional variants of this turbine are introduced in the article and theoretical aspects regarding losses in the draft tube. The theory is followed by computational simulations in Fluent and experiments using laser Doppler anemometry.

  20. Wind Turbines Wake Aerodynamics

    DEFF Research Database (Denmark)

    Vermeer, L.; Sørensen, Jens Nørkær; Crespo, A.

    2003-01-01

    The aerodynamics of horizontal axis wind turbine wakes is studied. The contents is directed towards the physics of power extraction by wind turbines and reviews both the near and the far wake region. For the near wake, the survey is restricted to uniform, steady and parallel flow conditions......, thereby excluding wind shear, wind speed and rotor setting changes and yawed conditions. The emphasis is put on measurements in controlled conditions.For the far wake, the survey focusses on both single turbines and wind farm effects, and the experimental and numerical work are reviewed; the main interest...... is to study how the far wake decays downstream, in order to estimate the effect produced in downstream turbines.The article is further restricted to horizontal axis wind turbines and excludes all other types of turbines....

  1. Superconducting Wind Turbine Generators

    Directory of Open Access Journals (Sweden)

    Yunying Pan

    2016-08-01

    Full Text Available Wind energy is well known as a renewable energy because its clean and less polluted characteristic, which is the foundation of development modern wind electricity. To find more efficient wind turbine is the focus of scientists around the world. Compared from conventional wind turbines, superconducting wind turbine generators have advantages at zero resistance, smaller size and lighter weight. Superconducting wind turbine will inevitably become the main trends in this area. This paper intends to introduce the basic concept and principle of superconductivity, and compare form traditional wind turbine to obtain superiority, then to summary three proposed machine concept.While superconductivity have difficulty  in modern technology and we also have proposed some challenges in achieving superconducting wind turbine finally.

  2. Fuel system for diesel engine with multi-stage heated

    Science.gov (United States)

    Ryzhov, Yu N.; Kuznetsov, Yu A.; Kolomeichenko, A. V.; Kuznetsov, I. S.; Solovyev, R. Yu; Sharifullin, S. N.

    2017-09-01

    The article describes a fuel system of a diesel engine with a construction tractor multistage heating, allowing the use of pure rapeseed oil as a diesel engine fuel. The paper identified the kinematic viscosity depending on the temperature and composition of the mixed fuel, supplemented by the existing recommendations on the use of mixed fuels based on vegetable oils and developed the device allowing use as fuel for diesel engines of biofuels based on vegetable oils.

  3. Multi-Stage Transportation Problem With Capacity Limit

    OpenAIRE

    I. Brezina; Z. Čičková; J. Pekár; M. Reiff

    2010-01-01

    The classical transportation problem can be applied in a more general way in practice. Related problems as Multi-commodity transportation problem, Transportation problems with different kind of vehicles, Multi-stage transportation problems, Transportation problem with capacity limit is an extension of the classical transportation problem considering the additional special condition. For solving such problems many optimization techniques (dynamic programming, linear programming, special algor...

  4. Integral performance optimum design for multistage solid propellant rocket motors

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hongtao (Shaanxi Power Machinery Institute (China))

    1989-04-01

    A mathematical model for integral performance optimization of multistage solid propellant rocket motors is presented. A calculation on a three-stage, volume-fixed, solid propellant rocket motor is used as an example. It is shown that the velocity at burnout of intermediate-range or long-range ballistic missile calculated using this model is four percent greater than that using the usual empirical method.

  5. A remark on empirical estimates in multistage stochastic programming

    Czech Academy of Sciences Publication Activity Database

    Kaňková, Vlasta

    2002-01-01

    Roč. 9, č. 17 (2002), s. 31-50 ISSN 1212-074X R&D Projects: GA ČR GA402/01/0539; GA ČR GA402/02/1015; GA ČR GA402/01/0034 Institutional research plan: CEZ:AV0Z1075907 Keywords : multistage stochastic programming * empirical estimates * Markov dependence Subject RIV: BB - Applied Statistics, Operational Research

  6. Flow in Pelton turbines

    OpenAIRE

    Furnes, Kjartan

    2013-01-01

    The flow in Pelton turbines is subsonic, turbulent, multiphase (water, air, and water vapor from cavitation), has high speeds, sharp gradients, free surface and dynamic boundary conditions. A static grid is unsuitable for modeling this mainly due to the turbine wheel and the liquid having a non-stationary relative motion.In recent times, significant progress in CFD simulation has been made, which also is relevant for Pelton turbines.Nevertheless, it is still common to perform costly model tes...

  7. Wind Turbine Technologies

    DEFF Research Database (Denmark)

    Hansen, Anca Daniela

    2017-01-01

    , and with or without gearboxes, using the latest in power electronics, aerodynamics, and mechanical drive train designs [4]. The main differences between all wind turbine concepts developed over the years, concern their electrical design and control. Today, the wind turbines on the market mix and match a variety......, the design of wind turbines has changed from being convention driven to being optimized driven within the operating regime and market environment. Wind turbine designs have progressed from fixed speed, passive controlled and with drive trains with gearboxes, to become variable speed, active controlled......,6] and to implement modern control system strategies....

  8. Preliminary Test of Friction disk type turbine for S-CO{sub 2} cycle application

    Energy Technology Data Exchange (ETDEWEB)

    Baik, Seungjoon; Kim, Hyeon Tae; Lee, Jeong Ik [KAIST, Daejeon (Korea, Republic of)

    2016-05-15

    Due to the relatively mild sodium-CO{sub 2} interaction, the S-CO{sub 2} Brayton cycle can reduce the accident consequence compared to the steam Rankine cycle. Also the S-CO{sub 2} power conversion cycle can achieve high efficiency for SFR core thermal condition. Moreover, the S-CO{sub 2} power cycle can reduce the total cycle footprint due to high density of the working fluid. However, the high pressure operating condition and low viscosity of the fluid cause difficulties in designing appropriate seals and multi-stage turbo machineries. To solve the problem for designing turbo machineries in a creative way, KAIST research team tested a friction disk type turbine concept for the S-CO{sub 2} cycle application. In this paper, the investigation of the Tesla turbine and preliminary test results with compressed air are covered. The KAIST research team investigated a friction disk type turbine, named as Tesla turbine, for the S-CO{sub 2} power cycle applications. Due to the robust design of the fiction disk type, the Tesla turbine technology can be utilized not only for S-CO{sub 2} turbo machinery but also for the multi-phase or sludge flow turbo machinery. The preliminary test of lab-scale Tesla turbine with compressed air was conducted. The high pressure vessel was manufactured for the S-CO{sub 2} operating condition. The test will be concentrated on the turbine efficiency measurement under various conditions and development of the design methodology.

  9. Guide to hydro turbines

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    This listing is a guide to turbines for hydroelectric projects of independent energy projects. The listing is in directory format and includes the supplier's name, the name of the supplier's contact, address, telephone and FAX numbers and a description of the company and the types of turbines, services and expertise available for energy projects. The listing is international in scope

  10. Improvement of turbine materials

    International Nuclear Information System (INIS)

    Jakobeit, W.; Pfeifer, J.P.

    1982-01-01

    Materials for turbine blades and rotors are discussed with a view to the following subjects: Long period creep behaviour, gas/metal reactions, fatigue behaviour in long-term and creep strength testing, fracture mechanics testing, creep/fatigue interactions, development of a turbine blade of TZM, jointing of TZM, decontamination. (orig./IHOE) [de

  11. Noise from wind turbines

    International Nuclear Information System (INIS)

    Andersen, B.; Larsen, P.

    1993-01-01

    Denmark has 3200 wind turbines with an installed maximum capacity of 418MW. The most important Danish research projects into wind turbine noise and the main results are listed. These date from 1983. Two comprehensive studies are currently in progress. The first is an analytical and empirical investigation of aerodynamic noise from wind turbine rotors and has so far dealt mainly with tip noise. The measurement method, using a hard board mounted microphone on the ground near the turbine, is described. Four different tip designs have been tested. Some examples of reference sound power level spectra for three of the designs are presented. During the past two years a computerbased data acquisition system has been used for real-time determination of sound power levels. The second study, which has just commenced, is on annoyance from wind turbine noise. It will include noise measurements, masking calculations and a social survey on the perceived nuisance. (UK)

  12. Graphene in turbine blades

    Science.gov (United States)

    Das, D. K.; Swain, P. K.; Sahoo, S.

    2016-07-01

    Graphene, the two-dimensional (2D) nanomaterial, draws interest of several researchers due to its many superior properties. It has extensive applications in numerous fields. A turbine is a hydraulic machine which extracts energy from a fluid and converts it into useful work. Recently, Gudukeya and Madanhire have tried to increase the efficiency of Pelton turbine. Beucher et al. have also tried the same by reducing friction between fluid and turbine blades. In this paper, we study the advantages of using graphene as a coating on Pelton turbine blades. It is found that the efficiency of turbines increases, running and maintenance cost is reduced with more power output. By the application of graphene in pipes, cavitation will be reduced, durability of pipes will increase, operation and maintenance cost of water power plants will be less.

  13. [Analysis of mitochondrial 12S rRNA and tRNA(Ser(UCN)) genes in patients with nonsyndromic sensorineural hearing loss from various regions of Russia].

    Science.gov (United States)

    Dzhemileva, L U; Posukh, O L; Tazetdinov, A M; Barashkov, N A; Zhuravskiĭ, S G; Ponidelko, S N; Markova, T G; Tadinova, V N; Fedorova, S A; Maksimova, N R; Khusnutdinova, E K

    2009-07-01

    Mitochondrial DNA (mtDNA) mutations play an important role in etiology of hereditary hearing loss. In various regions of the world, patients suffer from nonsyndromic sensorineural hearing loss initiated by aminoglycoside antibiotics. Mutations that had been shown as pathogenetically important for hearing function disturbance were identified in mitochondrial 12S rRNA and tRNA(Ser(UCN)) genes while pathogenic role of several DNA sequences requires additional studies. This work presents the results of studying the spectrum of mutations and polymorphic variations in mtDNA genes 12S rRNA and tRNA(Ser(UGN)) in 410 patients with nonsyndromal sensoneural hearing impairment/loss from the Volga Ural region, St Petersburg, Yakutia, and Altai and in 520 individuals with normal hearing, which represent several ethnic groups (Russians, Tatars, Bashkirs, Yakuts, Altaians) residing in the Russian Federation. Pathogenetically significant mutation A1555G (12S rRNA) was found in two families (from Yakutia and St Peresburg) with hearing loss, probably caused by treatment with aminoglucosides, and in the population sample of Yakuts with a frequency of 0.83%. Further research is needed to confirm the role in hearing impairment of mutations 961insC, 961insC(n), 961delTinsC(n), T961G, T1095C (12S rRNA) and G7444A, A7445C (tRNA(Ser(UGN revealed in the patients. In addition, in the patients and the population groups, polymorphic mt DNA variants were detected, which are characteristic also of other Eurasian populations both in spectrum and frequency.

  14. PREDICCIÓN DE LA ESTRUCTURA SECUNDARIA DEL tRNASer (UCN MITOCONDRIAL DEL FLEBOTOMÍNEO Lutzomyia hartmanni (DIPTERA: PSYCHODIDAE

    Directory of Open Access Journals (Sweden)

    Eduar Elías Bejarano Martínez

    2011-01-01

    Full Text Available Lutzomyia (Helcocyrtomyia hartmanni es un flebotomíneo implicado en la transmisión de Leishmania (Viannia colombiensis, uno de los agentes etiológicos de la leishmaniasis cutánea en Colombia. El objetivo de este trabajo fue explorar la utilidad potencial del RNA de transferencia mitocondrial para Serina (UCN (tRNASer, en la discriminación taxonómica de L. hartmanni. El DNA mitocondrial se extrajo, amplificó y secuenció a partir de material entomológico recolectado en Envigado, Antioquia, Colombia. El gen tRNASer de L. hartmanni mostró una longitud de 68 pares de bases, con un contenido AT del 80,9%. Éste se diferencia de los demás tRNASer de Lutzomyia conocidos a la fecha tanto por sustituciones en la secuencia primaria de nucleótidos como por los cambios que éstas generan en la estructura secundaria.  El número de apareamientos intracatenarios fue 7 en el brazo aceptor del aminoácido, 3 en el brazo dihidrouridina (DHU, 5 en el brazo del anticodón y 5 en el brazo ribotimidina-pseudouridina-citosina (TψC. El tamaño de las lupas DHU, anticodón, variable y TψC correspondió a 5, 7, 4 y 8 nucleótidos, respectivamente. La notoria ausencia de pares de bases no-Watson-Crick en los cuatro brazos del tRNASer de L. hartmanni, la distingue de otras especies de Lutzomyia.

  15. Interconnected levels of Multi-Stage Marketing – A Triadic approach

    DEFF Research Database (Denmark)

    Vedel, Mette; Geersbro, Jens; Ritter, Thomas

    2012-01-01

    must not only decide in general on the merits of multi-stage marketing for their firm, but must also decide on which level they will engage in multi-stage marketing. The triadic perspective enables a rich and multi-dimensional understanding of how different business relationships influence each other......Multi-stage marketing gains increasing attention as knowledge of and influence on the customer's customer become more critical for the firm's success. Despite this increasing managerial relevance, systematic approaches for analyzing multi-stage marketing are still missing. This paper conceptualizes...... different levels of multi-stage marketing and illustrates these stages with a case study. In addition, a triadic perspective is introduced as an analytical tool for multi-stage marketing research. The results from the case study indicate that multi-stage marketing exists on different levels. Thus, managers...

  16. Fundamentals of reliability engineering applications in multistage interconnection networks

    CERN Document Server

    Gunawan, Indra

    2014-01-01

    This book presents fundamentals of reliability engineering with its applications in evaluating reliability of multistage interconnection networks. In the first part of the book, it introduces the concept of reliability engineering, elements of probability theory, probability distributions, availability and data analysis.  The second part of the book provides an overview of parallel/distributed computing, network design considerations, and more.  The book covers a comprehensive reliability engineering methods and its practical aspects in the interconnection network systems. Students, engineers, researchers, managers will find this book as a valuable reference source.

  17. Multistage charged particle accelerator, with high-vacuum insulation

    International Nuclear Information System (INIS)

    Holl, P.

    1976-01-01

    A multistage charged-particle accelerator for operating with accelerating voltages higher than 150 kV is described. The device consists essentially of a high-voltage insulator, a source for producing charged particles, a Wehnelt cylinder, an anode, and a post-accelerating tube containing stack-wise positioned post-accelerating electrodes. A high vacuum is used for insulating the parts carrying the high voltages, and at least one cylindrical screen surrounding these parts is interposed between them and the vacuum vessel, which can itself also function as a cylindrical screen

  18. Multistage Spectral Relaxation Method for Solving the Hyperchaotic Complex Systems

    Directory of Open Access Journals (Sweden)

    Hassan Saberi Nik

    2014-01-01

    Full Text Available We present a pseudospectral method application for solving the hyperchaotic complex systems. The proposed method, called the multistage spectral relaxation method (MSRM is based on a technique of extending Gauss-Seidel type relaxation ideas to systems of nonlinear differential equations and using the Chebyshev pseudospectral methods to solve the resulting system on a sequence of multiple intervals. In this new application, the MSRM is used to solve famous hyperchaotic complex systems such as hyperchaotic complex Lorenz system and the complex permanent magnet synchronous motor. We compare this approach to the Runge-Kutta based ode45 solver to show that the MSRM gives accurate results.

  19. Study on multi-stage hydropyrolysis of coal in fixed-bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    Wang, N.; Li, W.; Li, B.-Q. [Chinese Academy of Sciences, Taiyuan (China). State Key Lab of Coal Conversion

    1999-07-01

    The composition and quantity of the oil in hydropyrolysis (HyPy) and multi-stage HyPy with high and slow heating rate were compared and the effect of multistage HyPy process on desulfurization was investigated. Multistage HyPy of lignite and high sulphur coal were investigated and the effects of residence time, heating rate and pressure on product yields were studied. 6 refs., 4 figs., 2 tabs.

  20. Turbine blade vibration dampening

    Science.gov (United States)

    Cornelius, C.C.; Pytanowski, G.P.; Vendituoli, J.S.

    1997-07-08

    The present turbine wheel assembly increases component life and turbine engine longevity. The combination of the strap and the opening combined with the preestablished area of the outer surface of the opening and the preestablished area of the outer circumferential surface of the strap and the friction between the strap and the opening increases the life and longevity of the turbine wheel assembly. Furthermore, the mass ``M`` or combined mass ``CM`` of the strap or straps and the centrifugal force assist in controlling vibrations and damping characteristics. 5 figs.

  1. Composite turbine bucket assembly

    Science.gov (United States)

    Liotta, Gary Charles; Garcia-Crespo, Andres

    2014-05-20

    A composite turbine blade assembly includes a ceramic blade including an airfoil portion, a shank portion and an attachment portion; and a transition assembly adapted to attach the ceramic blade to a turbine disk or rotor, the transition assembly including first and second transition components clamped together, trapping said ceramic airfoil therebetween. Interior surfaces of the first and second transition portions are formed to mate with the shank portion and the attachment portion of the ceramic blade, and exterior surfaces of said first and second transition components are formed to include an attachment feature enabling the transition assembly to be attached to the turbine rotor or disk.

  2. Hierarchical Cu precipitation in lamellated steel after multistage heat treatment

    Science.gov (United States)

    Liu, Qingdong; Gu, Jianfeng

    2017-09-01

    The hierarchical distribution of Cu-rich precipitates (CRPs) and related partitioning and segregation behaviours of solute atoms were investigated in a 1.54 Cu-3.51 Ni (wt.%) low-carbon high-strength low-alloy (HSLA) steel after multistage heat treatment by using the combination of electron backscatter diffraction (EBSD), transmission electron microscopy (TEM) and atom probe tomography (APT). Intercritical tempering at 725 °C of as-quenched lathlike martensitic structure leads to the coprecipitation of CRPs at the periphery of a carbide precipitate which is possibly in its paraequilibrium state due to distinct solute segregation at the interface. The alloyed carbide and CRPs provide constituent elements for each other and make the coprecipitation thermodynamically favourable. Meanwhile, austenite reversion occurs to form fresh secondary martensite (FSM) zone where is rich in Cu and pertinent Ni and Mn atoms, which gives rise to a different distributional morphology of CRPs with large size and high density. In addition, conventional tempering at 500 °C leads to the formation of nanoscale Cu-rich clusters in α-Fe matrix. As a consequence, three populations of CRPs are hierarchically formed around carbide precipitate, at FSM zone and in α-Fe matrix. The formation of different precipitated features can be turned by controlling diffusion pathways of related solute atoms and further to tailor mechanical properties via proper multistage heat treatments.

  3. A multi-stage stochastic transmission expansion planning method

    International Nuclear Information System (INIS)

    Akbari, Tohid; Rahimikian, Ashkan; Kazemi, Ahad

    2011-01-01

    Highlights: → We model a multi-stage stochastic transmission expansion planning problem. → We include available transfer capability (ATC) in our model. → Involving this criterion will increase the ATC between source and sink points. → Power system reliability will be increased and more money can be saved. - Abstract: This paper presents a multi-stage stochastic model for short-term transmission expansion planning considering the available transfer capability (ATC). The ATC can have a huge impact on the power market outcomes and the power system reliability. The transmission expansion planning (TEP) studies deal with many uncertainties, such as system load uncertainties that are considered in this paper. The Monte Carlo simulation method has been applied for generating different scenarios. A scenario reduction technique is used for reducing the number of scenarios. The objective is to minimize the sum of investment costs (IC) and the expected operation costs (OC). The solution technique is based on the benders decomposition algorithm. The N-1 contingency analysis is also done for the TEP problem. The proposed model is applied to the IEEE 24 bus reliability test system and the results are efficient and promising.

  4. Multi-stage fuzzy load frequency control using PSO

    International Nuclear Information System (INIS)

    Shayeghi, H.; Jalili, A.; Shayanfar, H.A.

    2008-01-01

    In this paper, a particle swarm optimization (PSO) based multi-stage fuzzy (PSOMSF) controller is proposed for solution of the load frequency control (LFC) problem in a restructured power system that operate under deregulation based on the bilateral policy scheme. In this strategy the control is tuned on line from the knowledge base and fuzzy inference, which request fewer sources and has two rule base sets. In the proposed method, for achieving the desired level of robust performance, exact tuning of membership functions is very important. Thus, to reduce the design effort and find a better fuzzy system control, membership functions are designed automatically by PSO algorithm, that has a strong ability to find the most optimistic results. The motivation for using the PSO technique is to reduce fuzzy system effort and take large parametric uncertainties into account. This newly developed control strategy combines the advantage of PSO and fuzzy system control techniques and leads to a flexible controller with simple stricture that is easy to implement. The proposed PSO based MSF (PSOMSF) controller is tested on a three-area restructured power system under different operating conditions and contract variations. The results of the proposed PSOMSF controller are compared with genetic algorithm based multi-stage fuzzy (GAMSF) control through some performance indices to illustrate its robust performance for a wide range of system parameters and load changes

  5. Multi-stage fuzzy load frequency control using PSO

    Energy Technology Data Exchange (ETDEWEB)

    Shayeghi, H. [Technical Engineering Department, University of Mohaghegh Ardabili, Ardabil (Iran); Jalili, A. [Islamic Azad University, Ardabil Branch, Ardabil (Iran); Shayanfar, H.A. [Center of Excellence for Power Automation and Operation, Electrical Engineering Department, Iran University of Science and Technology, Tehran (Iran)

    2008-10-15

    In this paper, a particle swarm optimization (PSO) based multi-stage fuzzy (PSOMSF) controller is proposed for solution of the load frequency control (LFC) problem in a restructured power system that operate under deregulation based on the bilateral policy scheme. In this strategy the control is tuned on line from the knowledge base and fuzzy inference, which request fewer sources and has two rule base sets. In the proposed method, for achieving the desired level of robust performance, exact tuning of membership functions is very important. Thus, to reduce the design effort and find a better fuzzy system control, membership functions are designed automatically by PSO algorithm, that has a strong ability to find the most optimistic results. The motivation for using the PSO technique is to reduce fuzzy system effort and take large parametric uncertainties into account. This newly developed control strategy combines the advantage of PSO and fuzzy system control techniques and leads to a flexible controller with simple stricture that is easy to implement. The proposed PSO based MSF (PSOMSF) controller is tested on a three-area restructured power system under different operating conditions and contract variations. The results of the proposed PSOMSF controller are compared with genetic algorithm based multi-stage fuzzy (GAMSF) control through some performance indices to illustrate its robust performance for a wide range of system parameters and load changes. (author)

  6. Multi-stage circulating fluidized bed syngas cooling

    Science.gov (United States)

    Liu, Guohai; Vimalchand, Pannalal; Guan, Xiaofeng; Peng, WanWang

    2016-10-11

    A method and apparatus for cooling hot gas streams in the temperature range 800.degree. C. to 1600.degree. C. using multi-stage circulating fluid bed (CFB) coolers is disclosed. The invention relates to cooling the hot syngas from coal gasifiers in which the hot syngas entrains substances that foul, erode and corrode heat transfer surfaces upon contact in conventional coolers. The hot syngas is cooled by extracting and indirectly transferring heat to heat transfer surfaces with circulating inert solid particles in CFB syngas coolers. The CFB syngas coolers are staged to facilitate generation of steam at multiple conditions and hot boiler feed water that are necessary for power generation in an IGCC process. The multi-stage syngas cooler can include internally circulating fluid bed coolers, externally circulating fluid bed coolers and hybrid coolers that incorporate features of both internally and externally circulating fluid bed coolers. Higher process efficiencies can be realized as the invention can handle hot syngas from various types of gasifiers without the need for a less efficient precooling step.

  7. Superconducting wind turbine generators

    DEFF Research Database (Denmark)

    Abrahamsen, Asger Bech; Mijatovic, Nenad; Seiler, Eugen

    2010-01-01

    , the main challenge of the superconducting direct drive technology is to prove that the reliability is superior to the alternative drive trains based on gearboxes or permanent magnets. A strategy of successive testing of superconducting direct drive trains in real wind turbines of 10 kW, 100 kW, 1 MW and 10......We have examined the potential of 10 MW superconducting direct drive generators to enter the European offshore wind power market and estimated that the production of about 1200 superconducting turbines until 2030 would correspond to 10% of the EU offshore market. The expected properties of future...... offshore turbines of 8 and 10 MW have been determined from an up-scaling of an existing 5 MW turbine and the necessary properties of the superconducting drive train are discussed. We have found that the absence of the gear box is the main benefit and the reduced weight and size is secondary. However...

  8. Turbine disintegration debris

    International Nuclear Information System (INIS)

    Holecek, M.; Martinec, P.; Malotin, V.; Peleska, P.; Voldrich, J.

    1997-01-01

    The determination, evaluation and analysis of possible unacceptable consequences of the disintegration turbine (turbo-set) missiles is a part of the wide conceived project put by the company Nuclear Power Plant Mochovce (NPPM), the Slovak Republic. The aim of the project is to take measures reducing the probability of striking a target of safety importance in NPPM by a turbine (turbo-set) missile below the prescribed limit of 10 -6 per turbine year. Following the IAEA Safety Guides, all potential events leading to the generation of a missile are to be analysed. It is necessary to evaluate the probability of unacceptable consequences of such missiles and analyse each event whose probability is not acceptable low. This complex problem thus carries especially: complex analysis of fragment generation; evaluation of the probability of unacceptable events; location of strike zones of possible turbine missiles; assessment the possibility of the turbo-set casing penetration; and projection of additional design requirements if necessary

  9. Monitoring of wind turbines

    Science.gov (United States)

    White, Jonathan R.; Adams, Douglas E.; Paquette, Josh

    2017-07-25

    Method and apparatus for determining the deflection or curvature of a rotating blade, such as a wind turbine blade or a helicopter blade. Also, methods and apparatus for establishing an inertial reference system on a rotating blade.

  10. Noise from wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Fegeant, Olivier [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Building Sciences

    2002-02-01

    A rapid growth of installed wind power capacity is expected in the next few years. However, the siting of wind turbines on a large scale raises concerns about their environmental impact, notably with respect to noise. To this end, variable speed wind turbines offer a promising solution for applications in densely populated areas like the European countries, as this design would enable an efficient utilisation of the masking effect due to ambient noise. In rural and recreational areas where wind turbines are sited, the ambient noise originates from the action of wind on the vegetation and about the listener's ear (pseudo-noise). It shows a wind speed dependence similar to that of the noise from a variable speed wind turbine and can therefore mask the latter for a wide range of conditions. However, a problem inherent to the design of these machines is their proclivity to pure tone generation, because of the enhanced difficulty of avoiding structural resonances in the mechanical parts. Pure tones are deemed highly annoying and are severely regulated by most noise policies. In relation to this problem, the vibration transmission of structure-borne sound to the tower of the turbine is investigated, in particular when the tower is stiffened at its upper end. Furthermore, since noise annoyance due to wind turbine is mostly a masking issue, the wind-related sources of ambient noise are studied and their masking potentials assessed. With this aim, prediction models for wind-induced vegetation noise and pseudo-noise have been developed. Finally, closely related to the effect of masking, is the difficulty, regularly encountered by local authorities and wind farm developers, to measure noise immission from wind turbines. A new measurement technique has thus been developed in the course of this work. Through improving the signal-to-noise ratio between wind turbine noise and ambient noise, the new technique yields more accurate measurement results.

  11. European wind turbine catalogue

    International Nuclear Information System (INIS)

    1994-01-01

    The THERMIE European Community programme is designed to promote the greater use of European technology and this catalogue contributes to the fulfillment of this aim by dissemination of information on 50 wind turbines from 30 manufacturers. These turbines are produced in Europe and are commercially available. The manufacturers presented produce and sell grid-connected turbines which have been officially approved in countries where this approval is acquired, however some of the wind turbines included in the catalogue have not been regarded as fully commercially available at the time of going to print. The entries, which are illustrated by colour photographs, give company profiles, concept descriptions, measured power curves, prices, and information on design and dimension, safety systems, stage of development, special characteristics, annual energy production, and noise pollution. Lists are given of wind turbine manufacturers and agents and of consultants and developers in the wind energy sector. Exchange rates used in the conversion of the prices of wind turbines are also given. Information can be found on the OPET network (organizations recognised by the European Commission as an Organization for the Promotion of Energy Technologies (OPET)). An article describes the development of the wind power industry during the last 10-15 years and another article on certification aims to give an overview of the most well-known and acknowledged type approvals currently issued in Europe. (AB)

  12. Wind turbines and health

    International Nuclear Information System (INIS)

    Rideout, K.; Copes, R.; Bos, C.

    2010-01-01

    This document summarized the potential health hazards associated with wind turbines, such as noise and low frequency sound, vibration and infrasound; electromagnetic fields (EMF); shadow flicker; and ice throw and structural failure. Various symptoms can be attributed to wind turbines, including dizziness, sleep disruption, and headaches. A review of available research regarding potential health affects to residents living in close proximity to wind turbines showed that the sound level associated with wind turbines at common residential setbacks is not sufficient to damage hearing, but may lead to annoyance and sleep disturbance. Research has shown that wind turbines are not a significant source of EMF exposure, and although shadows caused by the blades may be annoying, they are not likely to cause epileptic seizures at normal operational speeds. The risk of injury from ice throw can be minimized with setbacks of 200 to 400 m. Examples of Canadian wind turbine setback guidelines and regulations were also offered. It was concluded that setbacks and operational guidelines can be utilized in combination to address safety hazards, sound levels, land use issues, and impacts on people. 46 refs., 2 tabs., 2 figs.

  13. Wind turbines and infrasound

    International Nuclear Information System (INIS)

    Howe, B.

    2006-01-01

    This paper provided the results of a study conducted to assess the impacts of wind farm-induced infrasound on nearby residences and human populations. Infrasound occurs at frequencies below those considered as detectable by human hearing. Infrasonic levels caused by wind turbines are often similar to ambient levels of 85 dBG or lower that are caused by wind in the natural environment. This study examined the levels at which infrasound poses a threat to human health or can be considered as an annoyance. The study examined levels of infrasound caused by various types of wind turbines, and evaluated acoustic phenomena and characteristics associated with wind turbines. Results of the study suggested that infrasound near modern wind turbines is typically not perceptible to humans through either auditory or non-auditory mechanisms. However, wind turbines often create an audible broadband noise whose amplitude can be modulated at low frequencies. A review of both Canadian and international studies concluded that infrasound generated by wind turbines should not significantly impact nearby residences or human populations. 17 refs., 2 tabs., 4 figs

  14. Multi-Stage System for Automatic Target Recognition

    Science.gov (United States)

    Chao, Tien-Hsin; Lu, Thomas T.; Ye, David; Edens, Weston; Johnson, Oliver

    2010-01-01

    A multi-stage automated target recognition (ATR) system has been designed to perform computer vision tasks with adequate proficiency in mimicking human vision. The system is able to detect, identify, and track targets of interest. Potential regions of interest (ROIs) are first identified by the detection stage using an Optimum Trade-off Maximum Average Correlation Height (OT-MACH) filter combined with a wavelet transform. False positives are then eliminated by the verification stage using feature extraction methods in conjunction with neural networks. Feature extraction transforms the ROIs using filtering and binning algorithms to create feature vectors. A feedforward back-propagation neural network (NN) is then trained to classify each feature vector and to remove false positives. The system parameter optimizations process has been developed to adapt to various targets and datasets. The objective was to design an efficient computer vision system that can learn to detect multiple targets in large images with unknown backgrounds. Because the target size is small relative to the image size in this problem, there are many regions of the image that could potentially contain the target. A cursory analysis of every region can be computationally efficient, but may yield too many false positives. On the other hand, a detailed analysis of every region can yield better results, but may be computationally inefficient. The multi-stage ATR system was designed to achieve an optimal balance between accuracy and computational efficiency by incorporating both models. The detection stage first identifies potential ROIs where the target may be present by performing a fast Fourier domain OT-MACH filter-based correlation. Because threshold for this stage is chosen with the goal of detecting all true positives, a number of false positives are also detected as ROIs. The verification stage then transforms the regions of interest into feature space, and eliminates false positives using an

  15. Wind turbines and idiopathic symptoms

    DEFF Research Database (Denmark)

    Blanes-Vidal, Victoria; Schwartz, Joel

    2016-01-01

    Whether or not wind turbines pose a risk to human health is a matter of heated debate. Personal reactions to other environmental exposures occurring in the same settings as wind turbines may be responsible of the reported symptoms. However, these have not been accounted for in previous studies. We...... investigated whether there is an association between residential proximity to wind turbines and idiopathic symptoms, after controlling for personal reactions to other environmental co-exposures. We assessed wind turbine exposures in 454 residences as the distance to the closest wind turbine (Dw) and number...... of wind turbines

  16. A Methodology for Optimization in Multistage Industrial Processes: A Pilot Study

    Directory of Open Access Journals (Sweden)

    Piotr Jarosz

    2015-01-01

    Full Text Available The paper introduces a methodology for optimization in multistage industrial processes with multiple quality criteria. Two ways of formulation of optimization problem and four different approaches to solve the problem are considered. Proposed methodologies were tested first on a virtual process described by benchmark functions and next were applied in optimization of multistage lead refining process.

  17. Novel methodology for wide-ranged multistage morphing waverider based on conical theory

    Science.gov (United States)

    Liu, Zhen; Liu, Jun; Ding, Feng; Xia, Zhixun

    2017-11-01

    This study proposes the wide-ranged multistage morphing waverider design method. The flow field structure and aerodynamic characteristics of multistage waveriders are also analyzed. In this method, the multistage waverider is generated in the same conical flowfield, which contains a free-stream surface and different compression-stream surfaces. The obtained results show that the introduction of the multistage waverider design method can solve the problem of aerodynamic performance deterioration in the off-design state and allow the vehicle to always maintain the optimal flight state. The multistage waverider design method, combined with transfiguration flight strategy, can lead to greater design flexibility and the optimization of hypersonic wide-ranged waverider vehicles.

  18. Multistage switching hardware and software implementations for student experiment purpose

    Science.gov (United States)

    Sani, A.; Suherman

    2018-02-01

    Current communication and internet networks are underpinned by the switching technologies that interconnect one network to the others. Students’ understanding on networks rely on how they conver the theories. However, understanding theories without touching the reality may exert spots in the overall knowledge. This paper reports the progress of the multistage switching design and implementation for student laboratory activities. The hardware and software designs are based on three stages clos switching architecture with modular 2x2 switches, controlled by an arduino microcontroller. The designed modules can also be extended for batcher and bayan switch, and working on circuit and packet switching systems. The circuit analysis and simulation show that the blocking probability for each switch combinations can be obtained by generating random or patterned traffics. The mathematic model and simulation analysis shows 16.4% blocking probability differences as the traffic generation is uniform. The circuits design components and interfacing solution have been identified to allow next step implementation.

  19. Multistage audiovisual integration of speech: dissociating identification and detection.

    Science.gov (United States)

    Eskelund, Kasper; Tuomainen, Jyrki; Andersen, Tobias S

    2011-02-01

    Speech perception integrates auditory and visual information. This is evidenced by the McGurk illusion where seeing the talking face influences the auditory phonetic percept and by the audiovisual detection advantage where seeing the talking face influences the detectability of the acoustic speech signal. Here, we show that identification of phonetic content and detection can be dissociated as speech-specific and non-specific audiovisual integration effects. To this end, we employed synthetically modified stimuli, sine wave speech (SWS), which is an impoverished speech signal that only observers informed of its speech-like nature recognize as speech. While the McGurk illusion only occurred for informed observers, the audiovisual detection advantage occurred for naïve observers as well. This finding supports a multistage account of audiovisual integration of speech in which the many attributes of the audiovisual speech signal are integrated by separate integration processes.

  20. Nonlinear dynamics modelling of multistage micro-planetary gear transmission

    Directory of Open Access Journals (Sweden)

    Li Jianying

    2018-01-01

    Full Text Available The transmission structure of a 2K-H multistage micro-planetary gear transmission reducer is described in detail, and three assumptions are supposed in dynamic modelling. On basis of these assumptions, a three stages 2K-H micro-planetary gear transmission dynamic model is established, in which the relative displacement each meshing gear pairs can be obtained after including the comprehensive transmission error. According to gear kinematics, the friction arms between the sun gear, the ring gear and the nth planet are also obtained, and the friction coefficient in the mixed elastohydrodynamic lubrication is considered, the transmission system motion differential equations are obtained, including above factors and the time-varying meshing stiffness, damping and backlash, inter-stage coupling stiffness, it can be provided an theoretical foundation for further analysing the parameter sensitivity, dynamic stability and designing.

  1. Desulfurization and denitrogenation of coal during multi-stage hydropyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Wang, N.; Li, W.; Li, B. [Chinese Academy of Sciences, Taiyuan (China). State Key Lab of Coal Conversion

    2001-02-01

    The elemental composition of char of high sulfur Hongmiao coal in multi-stage hydropyrolysis (MHyPy) with different heating rates were analysed and compared with that from normal hydropyrolysis (HyPy). The results illustrated that the sulfur removal in MHyPy was greater than that in HyPy, and more sulfur was evolved as the easily recycled gas H{sub 2}S. Similar with the situation of sulfur, more nitrogen transferred to the gas phase easily to be dealt with and the clean char was obtained. During MHyPy the extent of desulfurization and denitrogenation was more remarkable at high rate than that at slow heating rate. 8 refs., 2 figs., 2 tabs.

  2. Thermogravimetric analysis of multi-stage hydropyrolysis of different coals

    Energy Technology Data Exchange (ETDEWEB)

    Li, W.; Wang, N.; Li, B [Chinese Academy of Sciences, Taiyuan (China). State Key Lab. of Coal Conversion

    2001-09-01

    Based on the characteristic of hydropyrolysis (HyPy), a multi-stage MHyPy of different coals was investigated using thermogravimetry. The results show that keeping the near peak temperature for some time in HyPy process can obviously increase the conversion rate, which is believed due to the full match between formation rate of free radicals and supply of hydrogen. The fast heating in MHyPy process results in the same conversion rate as that of the slow heating in HyPy process, which leads to the less reaction time and high yield of oil. The effect of MHyPy depends on the coal structure itself and it is notable for the coal with high H/C ratio. This suggests that the external hydrogen promotes the reaction between intrinsic hydrogen and free radicals. The MHyPy improves the removal of sulfur and nitrogen. 5 refs., 7 figs., 2 tabs.

  3. Process analysis of catalytic multi-stage hydropyrolysis of lignite

    Energy Technology Data Exchange (ETDEWEB)

    Li, W.; Wang, N.; Li, B. [Chinese Academy of Sciences, Taiyuan (China). Inst. of Coal Chemistry, State Key Laboratory of Coal Conversion

    2002-08-01

    The process and the mechanism of multi-stage hydropyrolysis (MHyPy) of coal were investigated by analyzing the products of different MHyPy processes in detail. The results showed that the suitable holding temperature was near the peak temperature (350-500{degree}C) at which more free radicals were produced rapidly, thus more oil was formed and the hydrogen utilization efficiency was increased. The cleavage of organic functional groups in char from MHyPy was mostly affected by the pyrolysis temperature. The effect of retention was to change the product distribution through stabilization of the free radicals and hydrogenation of the heavier products. In the holding stage the specific surface area and average pore volume of the char were increased due to the escape of more hydrogenation products. 18 refs., 8 figs., 3 tabs.

  4. Silicon nanowire networks for multi-stage thermoelectric modules

    International Nuclear Information System (INIS)

    Norris, Kate J.; Garrett, Matthew P.; Zhang, Junce; Coleman, Elane; Tompa, Gary S.; Kobayashi, Nobuhiko P.

    2015-01-01

    Highlights: • Fabricated flexible single, double, and quadruple stacked Si thermoelectric modules. • Measured an enhanced power production of 27%, showing vertical stacking is scalable. • Vertically scalable thermoelectric module design of semiconducting nanowires. • Design can utilize either p or n-type semiconductors, both types are not required. • ΔT increases with thickness therefore power/area can increase as modules are stacked. - Abstract: We present the fabrication and characterization of single, double, and quadruple stacked flexible silicon nanowire network based thermoelectric modules. From double to quadruple stacked modules, power production increased 27%, demonstrating that stacking multiple nanowire thermoelectric devices in series is a scalable method to generate power by supplying larger temperature gradient. We present a vertically scalable multi-stage thermoelectric module design using semiconducting nanowires, eliminating the need for both n-type and p-type semiconductors for modules

  5. Multistage audiovisual integration of speech: dissociating identification and detection

    DEFF Research Database (Denmark)

    Eskelund, Kasper; Tuomainen, Jyrki; Andersen, Tobias

    2011-01-01

    Speech perception integrates auditory and visual information. This is evidenced by the McGurk illusion where seeing the talking face influences the auditory phonetic percept and by the audiovisual detection advantage where seeing the talking face influences the detectability of the acoustic speech...... signal. Here we show that identification of phonetic content and detection can be dissociated as speech-specific and non-specific audiovisual integration effects. To this end, we employed synthetically modified stimuli, sine wave speech (SWS), which is an impoverished speech signal that only observers...... informed of its speech-like nature recognize as speech. While the McGurk illusion only occurred for informed observers the audiovisual detection advantage occurred for naïve observers as well. This finding supports a multi-stage account of audiovisual integration of speech in which the many attributes...

  6. Applying a punch with microridges in multistage deep drawing processes.

    Science.gov (United States)

    Lin, Bor-Tsuen; Yang, Cheng-Yu

    2016-01-01

    The developers of high aspect ratio components aim to minimize the processing stages in deep drawing processes. This study elucidates the application of microridge punches in multistage deep drawing processes. A microridge punch improves drawing performance, thereby reducing the number of stages required in deep forming processes. As an example, the original eight-stage deep forming process for a copper cylindrical cup with a high aspect ratio was analyzed by finite element simulation. Microridge punch designs were introduced in Stages 4 and 7 to replace the original punches. In addition, Stages 3 and 6 were eliminated. Finally, these changes were verified through experiments. The results showed that the microridge punches reduced the number of deep drawing stages yielding similar thickness difference percentages. Further, the numerical and experimental results demonstrated good consistency in the thickness distribution.

  7. Next Generation Wind Turbine

    Energy Technology Data Exchange (ETDEWEB)

    Cheraghi, S. Hossein [Western New England Univ., Springfield, MA (United States); Madden, Frank [FloDesign Wind Turbine Corp., Waltham, MA (United States)

    2012-09-01

    The goal of this collaborative effort between Western New England University's College of Engineering and FloDesign Wind Turbine (FDWT) Corporation to wok on a novel areodynamic concept that could potentially lead to the next generation of wind turbines. Analytical studies and early scale model tests of FDWT's Mixer/Ejector Wind Turbine (MEWT) concept, which exploits jet-age advanced fluid dynamics, indicate that the concept has the potential to significantly reduce the cost of electricity over conventional Horizontal Axis Wind Turbines while reducing land usage. This project involved the design, fabrication, and wind tunnel testing of components of MEWT to provide the research and engineering data necessary to validate the design iterations and optimize system performance. Based on these tests, a scale model prototype called Briza was designed, fabricated, installed and tested on a portable tower to investigate and improve the design system in real world conditions. The results of these scale prototype efforts were very promising and have contributed significantly to FDWT's ongoing development of a product scale wind turbine for deployment in multiple locations around the U.S. This research was mutually beneficial to Western New England University, FDWT, and the DOE by utilizing over 30 student interns and a number of faculty in all efforts. It brought real-world wind turbine experience into the classroom to further enhance the Green Engineering Program at WNEU. It also provided on-the-job training to many students, improving their future employment opportunities, while also providing valuable information to further advance FDWT's mixer-ejector wind turbine technology, creating opportunities for future project innovation and job creation.

  8. Robust modified GA based multi-stage fuzzy LFC

    International Nuclear Information System (INIS)

    Shayeghi, H.; Jalili, A.; Shayanfar, H.A.

    2007-01-01

    In this paper, a robust genetic algorithm (GA) based multi-stage fuzzy (MSF) controller is proposed for solution of the load frequency control (LFC) problem in a restructured power system that operates under deregulation based on the bilateral policy scheme. In this strategy, the control signal is tuned online from the knowledge base and the fuzzy inference, which request fewer sources and has two rule base sets. In the proposed method, for achieving the desired level of robust performance, exact tuning of the membership functions is very important. Thus, to reduce the design effort and find a better fuzzy system control, membership functions are designed automatically by modified genetic algorithms. The classical genetic algorithms are powerful search techniques to find the global optimal area. However, the global optimum value is not guaranteed using this method, and the speed of the algorithm's convergence is extremely reduced too. To overcome this drawback, a modified genetic algorithm is being used to tune the membership functions of the proposed MSF controller. The effectiveness of the proposed method is demonstrated on a three area restructured power system with possible contracted scenarios under large load demand and area disturbances in comparison with the multi-stage fuzzy and classical fuzzy PID controllers through FD and ITAE performance indices. The results evaluation shows that the proposed control strategy achieves good robust performance for a wide range of system parameters and load changes in the presence of system nonlinearities and is superior to the other controllers. Moreover, this newly developed control strategy has a simple structure, does not require an accurate model of the plant and is fairly easy to implement, which can be useful for the real world complex power systems

  9. Robust modified GA based multi-stage fuzzy LFC

    Energy Technology Data Exchange (ETDEWEB)

    Shayeghi, H. [Technical Engineering Department, The University of Mohaghegh Ardebili, Daneshkah St., Ardebil (Iran); Jalili, A. [Electrical Engineering Group, Islamic Azad University, Ardebil Branch, Ardebil (Iran); Shayanfar, H.A. [Electrical Engineering Department, Iran University of Science and Technology, Tehran (Iran)

    2007-05-15

    In this paper, a robust genetic algorithm (GA) based multi-stage fuzzy (MSF) controller is proposed for solution of the load frequency control (LFC) problem in a restructured power system that operates under deregulation based on the bilateral policy scheme. In this strategy, the control signal is tuned online from the knowledge base and the fuzzy inference, which request fewer sources and has two rule base sets. In the proposed method, for achieving the desired level of robust performance, exact tuning of the membership functions is very important. Thus, to reduce the design effort and find a better fuzzy system control, membership functions are designed automatically by modified genetic algorithms. The classical genetic algorithms are powerful search techniques to find the global optimal area. However, the global optimum value is not guaranteed using this method, and the speed of the algorithm's convergence is extremely reduced too. To overcome this drawback, a modified genetic algorithm is being used to tune the membership functions of the proposed MSF controller. The effectiveness of the proposed method is demonstrated on a three area restructured power system with possible contracted scenarios under large load demand and area disturbances in comparison with the multi-stage fuzzy and classical fuzzy PID controllers through FD and ITAE performance indices. The results evaluation shows that the proposed control strategy achieves good robust performance for a wide range of system parameters and load changes in the presence of system nonlinearities and is superior to the other controllers. Moreover, this newly developed control strategy has a simple structure, does not require an accurate model of the plant and is fairly easy to implement, which can be useful for the real world complex power systems. (author)

  10. Gas turbine engine turbine blade damaging estimate in maintenance

    Directory of Open Access Journals (Sweden)

    Ель-Хожайрі Хусейн

    2004-01-01

    Full Text Available  The factors determining character and intensity of corrosive damages of gas turbine blades are analyzed in the article. The classification of detrimental impurities polluting gas turbine airflow duct and injuring blade erosion damages are given. Common features of the method of turbine blade corrosive damage estimation are shown in the article.

  11. Wind turbine noise diagnostics

    International Nuclear Information System (INIS)

    Richarz, W.; Richarz, H.

    2009-01-01

    This presentation proposed a self-consistent model for broad-band noise emitted from modern wind turbines. The simple source model was consistent with the physics of sound generation and considered the unique features of wind turbines. Although the acoustics of wind turbines are similar to those of conventional propellers, the dimensions of wind turbines pose unique challenges in diagnosing noise emission. The general features of the sound field were deduced. Source motion and source directivity appear to be responsible for amplitude variations. The amplitude modulation is likely to make wind-turbine noise more audible, and may be partly responsible for annoyance that has been reported in the literature. Acoustic array data suggests that broad-band noise is emitted predominantly during the downward sweep of each rotor blade. Source motion and source directivity account for the observed pattern. Rotor-tower interaction effects are of lesser importance. Predicted amplitude modulation ranges from 1 dB to 6dB. 2 refs., 9 figs.

  12. Deflector plants turbine aeration

    International Nuclear Information System (INIS)

    Miller, D.E.; Sheppard, A.R.; Widener, D.W.

    1991-01-01

    Water quality requirements have become a focal point in recent re-licensing of hydroelectric projects. The Federal Energy Regulatory Commission has significantly increased the relevance of license conditions to insure that turbine discharges meet state or other specific criteria for dissolved oxygen (D.O.). Due to naturally occurring depletion of D.O. at increased depths in large reservoirs, water withdrawn from this strata may result in unacceptably low levels of D.O. Different researchers have evaluated various methods of improving D.O. content in hydro turbine discharges, including; diffusers, weirs, oxygen injection, and variations of turbine venting. The authors describe an approach called deflector plate turbine aeration. This computer based, engineered approach allows systems to be evaluated, designed, and installed with predictable performance and costs. Many experts in this field now agree that, to the extent practical, turbine venting offers the most dependable, maintenance free, and cost effective solution to the low D.O. problem. The approach presented in this paper has resulted in proven results

  13. Floating wind turbine system

    Science.gov (United States)

    Viterna, Larry A. (Inventor)

    2009-01-01

    A floating wind turbine system with a tower structure that includes at least one stability arm extending therefrom and that is anchored to the sea floor with a rotatable position retention device that facilitates deep water installations. Variable buoyancy for the wind turbine system is provided by buoyancy chambers that are integral to the tower itself as well as the stability arm. Pumps are included for adjusting the buoyancy as an aid in system transport, installation, repair and removal. The wind turbine rotor is located downwind of the tower structure to allow the wind turbine to follow the wind direction without an active yaw drive system. The support tower and stability arm structure is designed to balance tension in the tether with buoyancy, gravity and wind forces in such a way that the top of the support tower leans downwind, providing a large clearance between the support tower and the rotor blade tips. This large clearance facilitates the use of articulated rotor hubs to reduced damaging structural dynamic loads. Major components of the turbine can be assembled at the shore and transported to an offshore installation site.

  14. Wind turbine control and monitoring

    CERN Document Server

    Luo, Ningsu; Acho, Leonardo

    2014-01-01

    Maximizing reader insights into the latest technical developments and trends involving wind turbine control and monitoring, fault diagnosis, and wind power systems, 'Wind Turbine Control and Monitoring' presents an accessible and straightforward introduction to wind turbines, but also includes an in-depth analysis incorporating illustrations, tables and examples on how to use wind turbine modeling and simulation software.   Featuring analysis from leading experts and researchers in the field, the book provides new understanding, methodologies and algorithms of control and monitoring, comput

  15. Ultra-Cold Neutrons (UCN)

    Data.gov (United States)

    Federal Laboratory Consortium — Researchers working at the Los Alamos Neutron Science Center and eight other member institutions of an international collaboration are constructing the most intense...

  16. Wind Turbine With Concentric Ducts

    Science.gov (United States)

    Muhonen, A. J.

    1983-01-01

    Wind Turbine device is relatively compact and efficient. Converging inner and outer ducts increase pressure difference across blades of wind turbine. Turbine shaft drives alternator housed inside exit cone. Suitable for installation on such existing structures as water towers, barns, houses, and commercial buildings.

  17. Wind turbine spoiler

    Science.gov (United States)

    Sullivan, W.N.

    An aerodynamic spoiler system for a vertical axis wind turbine includes spoilers on the blades initially stored near the rotor axis to minimize drag. A solenoid latch adjacent the central support tower releases the spoilers and centrifugal force causes the spoilers to move up the turbine blades away from the rotor axis, thereby producing a braking effect and actual slowing of the associated wind turbine, if desired. The spoiler system can also be used as an infinitely variable power control by regulated movement of the spoilers on the blades over the range between the undeployed and fully deployed positions. This is done by the use of a suitable powered reel and cable located at the rotor tower to move the spoilers.

  18. Steam turbine installations

    International Nuclear Information System (INIS)

    Bainbridge, A.

    1976-01-01

    The object of the arrangement described is to enable raising steam for driving steam turbines in a way suited to operating with liquid metals, such as Na, as heat transfer medium. A preheated water feed, in heat transfer relationship with the liquid metals, is passed through evaporator and superheater stages, and the superheated steam is supplied to the highest pressure stage of the steam turbine arrangement. Steam extracted intermediate the evaporator and superheater stages is employed to provide reheat for the lower pressure stage of the steam turbine. Only a major portion of the preheated water feed may be evaporated and this portion separated and supplied to the superheater stage. The feature of 'steam to steam' reheat avoids a second liquid metal heat transfer and hence represents a simplification. It also reduces the hazard associated with possible steam-liquid metal contact. (U.K.)

  19. Hydro turbines: An introduction

    International Nuclear Information System (INIS)

    Gordon, J.L.

    1993-01-01

    The various types of hydraulic turbines currently used in hydroelectric power plants are described. The descriptions are intended for use by non-engineers who are concerned with fish passage and fish mortality at a hydro power facility. Terminology used in the hydro industry is explained. Since the extent of cavitation is one of the factors affecting mortality rates of fish passing through hydraulic turbines, an equation is introduced which measures the extent of cavitation likely to be experienced in a turbine. An example of how the cavitation index can be calculated is provided for two typical power plants. The relation between certain parameters of power plant operation and the extent of cavitation, and therefore of fish mortality, is illustrated. 2 refs., 14 figs

  20. Variable stator radial turbine

    Science.gov (United States)

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

    1984-01-01

    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.

  1. Noise from wind turbines

    International Nuclear Information System (INIS)

    Andersen, B.; Jakobsen, J.

    1992-11-01

    Based on a previous project concerning the calculation of the amount of noise emanating from wind turbine arrays, this one examines the subject further by investigating whether there could be significant differences in the amount of noise made by individual wind turbines in an array, and whether the noise is transmitted in varying directions - so that when it is carried in the same direction as the wind blows it would appear to be louder. The aim was also to determine whether the previously used method of calculation lacked precision. It was found that differences in noise niveaux related to individual wind turbines were insignificant and that noise was not so loud when it was not borne in the direction of the wind. It was necessary to change the method of calculation as reckoning should include the influence of the terrain, wind velocity and distance. The measuring and calculation methods are exemplified and the resulting measurements are presented in detail. (AB)

  2. Aeroservoelasticity of Wind Turbines

    DEFF Research Database (Denmark)

    Kallesøe, Bjarne Skovmose

    2007-01-01

    This thesis deals with the fundamental aeroelastic interaction between structural motion, Pitch action and control for a wind turbine blade. As wind turbines become larger, the interaction between pitch action, blade motion, aerodynamic forces, and control become even more important to understand......, and furthermore linear and therefore suitable for control design. The development of the primary aeroelastic blade model is divided into four steps: 1) Nonlinear partial differential equations (PDEs) of structural blade motion are derived together with equations of pitch action and rotor speed; the individual...... to a 2D blade section model, and it can be used instead of this in many applications, giving a transparent connection to a real wind turbine blade. In this work the aeroelastic blade model is used to analyze interaction between pitch action, blade motion and wind speed variations. Furthermore the model...

  3. Wind Turbine Acoustics

    Science.gov (United States)

    Hubbard, Harvey H.; Shepherd, Kevin P.

    2009-01-01

    Wind turbine generators, ranging in size from a few kilowatts to several megawatts, are producing electricity both singly and in wind power stations that encompass hundreds of machines. Many installations are in uninhabited areas far from established residences, and therefore there are no apparent environmental impacts in terms of noise. There is, however, the potential for situations in which the radiated noise can be heard by residents of adjacent neighborhoods, particularly those neighborhoods with low ambient noise levels. A widely publicized incident of this nature occurred with the operation of the experimental Mod-1 2-MW wind turbine, which is described in detail elsewhere. Pioneering studies which were conducted at the Mod-1 site on the causes and remedies of noise from wind turbines form the foundation of much of the technology described in this chapter.

  4. Micro turbines on gas

    International Nuclear Information System (INIS)

    Kotevski, Darko

    2003-01-01

    Microturbines are small gas turbine engines that drive a generator with sizes ranging from 30-350 kW. Although similar in function to bigger gas turbines, their simple radial flow turbine and high-speed generator offer better performance, greater reliability, longer service intervals, reduced maintenance lower emission and lower noise. Microturbines can generate power continuously and very economically to reduce electricity costs or they can be operated selectively for peak shaving. These benefits are further enhanced by the economics of using the microturbine's waste heat for hot water needs or other heating applications. That is why on-site microturbine power is widely used for independent production of electricity and heat in industrial and commercial facilities, hotels, hospitals, office buildings, residential buildings etc. (Original)

  5. Steam generators, turbines, and condensers. Volume six

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    Volume six covers steam generators (How steam is generated, steam generation in a PWR, vertical U-tube steam generators, once-through steam generators, how much steam do steam generators make?), turbines (basic turbine principles, impulse turbines, reaction turbines, turbine stages, turbine arrangements, turbine steam flow, steam admission to turbines, turbine seals and supports, turbine oil system, generators), and condensers (need for condensers, basic condenser principles, condenser arrangements, heat transfer in condensers, air removal from condensers, circulating water system, heat loss to the circulating water system, factors affecting condenser performance, condenser auxiliaries)

  6. Offshore Wind Turbine Design

    DEFF Research Database (Denmark)

    Frandsen, Sten; Hansen, Erik Asp; Ibsen, Lars Bo

    2006-01-01

    Current offshore wind turbine design methods have matured to a 1st generation state, manifested in the draft of a possible standard, IEC 61400-3 (2005). It is now time to investigate the possibilities of improving existing methods. To do so in an efficient manner a clear identification of the most...... important uncertainty drivers specific for offshore wind turbine design loads is required. Describing the initial efforts in a Danish research project, the paper points to focal points for research and development. These are mainly: soil-structure interaction, improved modelling of wave loads from deep...

  7. Vertical axis wind turbines

    Science.gov (United States)

    Krivcov, Vladimir [Miass, RU; Krivospitski, Vladimir [Miass, RU; Maksimov, Vasili [Miass, RU; Halstead, Richard [Rohnert Park, CA; Grahov, Jurij [Miass, RU

    2011-03-08

    A vertical axis wind turbine is described. The wind turbine can include a top ring, a middle ring and a lower ring, wherein a plurality of vertical airfoils are disposed between the rings. For example, three vertical airfoils can be attached between the upper ring and the middle ring. In addition, three more vertical airfoils can be attached between the lower ring and the middle ring. When wind contacts the vertically arranged airfoils the rings begin to spin. By connecting the rings to a center pole which spins an alternator, electricity can be generated from wind.

  8. Vertical axis wind turbine

    International Nuclear Information System (INIS)

    Obretenov, V.; Tsalov, T.; Chakarov, T.

    2012-01-01

    In recent years, the interest in wind turbines with vertical axis noticeably increased. They have some important advantages: low cost, relatively simple structure, reliable packaging system of wind aggregate long period during which require no maintenance, low noise, independence of wind direction, etc.. The relatively low efficiency, however, makes them applicable mainly for small facilities. The work presents a methodology and software for approximately aerodynamic design of wind turbines of this type, and also analyzed the possibility of improving the efficiency of their workflow

  9. ADVANCED TURBINE SYSTEMS PROGRAM

    Energy Technology Data Exchange (ETDEWEB)

    Gregory Gaul

    2004-04-21

    Natural gas combustion turbines are rapidly becoming the primary technology of choice for generating electricity. At least half of the new generating capacity added in the US over the next twenty years will be combustion turbine systems. The Department of Energy has cosponsored with Siemens Westinghouse, a program to maintain the technology lead in gas turbine systems. The very ambitious eight year program was designed to demonstrate a highly efficient and commercially acceptable power plant, with the ability to fire a wide range of fuels. The main goal of the Advanced Turbine Systems (ATS) Program was to develop ultra-high efficiency, environmentally superior and cost effective competitive gas turbine systems for base load application in utility, independent power producer and industrial markets. Performance targets were focused on natural gas as a fuel and included: System efficiency that exceeds 60% (lower heating value basis); Less than 10 ppmv NO{sub x} emissions without the use of post combustion controls; Busbar electricity that are less than 10% of state of the art systems; Reliability-Availability-Maintainability (RAM) equivalent to current systems; Water consumption minimized to levels consistent with cost and efficiency goals; and Commercial systems by the year 2000. In a parallel effort, the program was to focus on adapting the ATS engine to coal-derived or biomass fuels. In Phase 1 of the ATS Program, preliminary investigators on different gas turbine cycles demonstrated that net plant LHV based efficiency greater than 60% was achievable. In Phase 2 the more promising cycles were evaluated in greater detail and the closed-loop steam-cooled combined cycle was selected for development because it offered the best solution with least risk for achieving the ATS Program goals for plant efficiency, emissions, cost of electricity and RAM. Phase 2 also involved conceptual ATS engine and plant design and technology developments in aerodynamics, sealing

  10. Multiple piece turbine airfoil

    Science.gov (United States)

    Kimmel, Keith D; Wilson, Jr., Jack W.

    2010-11-02

    A turbine airfoil, such as a rotor blade or a stator vane, for a gas turbine engine, the airfoil formed as a shell and spar construction with a plurality of dog bone struts each mounted within openings formed within the shell and spar to allow for relative motion between the spar and shell in the airfoil chordwise direction while also forming a seal between adjacent cooling channels. The struts provide the seal as well as prevent bulging of the shell from the spar due to the cooling air pressure.

  11. Aerodynamics of wind turbines

    CERN Document Server

    Hansen, Martin O L

    2015-01-01

    Aerodynamics of Wind Turbines is the established essential text for the fundamental solutions to efficient wind turbine design. Now in its third edition, it has been substantially updated with respect to structural dynamics and control. The new control chapter now includes details on how to design a classical pitch and torque regulator to control rotational speed and power, while the section on structural dynamics has been extended with a simplified mechanical system explaining the phenomena of forward and backward whirling modes. Readers will also benefit from a new chapter on Vertical Axis W

  12. Ceramic gas turbine shroud

    Science.gov (United States)

    Shi, Jun; Green, Kevin E.

    2014-07-22

    An example gas turbine engine shroud includes a first annular ceramic wall having an inner side for resisting high temperature turbine engine gasses and an outer side with a plurality of radial slots. A second annular metallic wall is positioned radially outwardly of and enclosing the first annular ceramic wall and has a plurality of tabs in communication with the slot of the first annular ceramic wall. The tabs of the second annular metallic wall and slots of the first annular ceramic wall are in communication such that the first annular ceramic wall and second annular metallic wall are affixed.

  13. An Optical Fiber Bundle Sensor for Tip Clearance and Tip Timing Measurements in a Turbine Rig

    Directory of Open Access Journals (Sweden)

    María Asunción Illarramendi

    2013-06-01

    Full Text Available When it comes to measuring blade-tip clearance or blade-tip timing in turbines, reflective intensity-modulated optical fiber sensors overcome several traditional limitations of capacitive, inductive or discharging probe sensors. This paper presents the signals and results corresponding to the third stage of a multistage turbine rig, obtained from a transonic wind-tunnel test. The probe is based on a trifurcated bundle of optical fibers that is mounted on the turbine casing. To eliminate the influence of light source intensity variations and blade surface reflectivity, the sensing principle is based on the quotient of the voltages obtained from the two receiving bundle legs. A discrepancy lower than 3% with respect to a commercial sensor was observed in tip clearance measurements. Regarding tip timing measurements, the travel wave spectrum was obtained, which provides the average vibration amplitude for all blades at a particular nodal diameter. With this approach, both blade-tip timing and tip clearance measurements can be carried out simultaneously. The results obtained on the test turbine rig demonstrate the suitability and reliability of the type of sensor used, and suggest the possibility of performing these measurements in real turbines under real working conditions.

  14. Feet swelling in a multistage ultraendurance triathlete: a case study

    Directory of Open Access Journals (Sweden)

    Knechtle B

    2015-10-01

    Full Text Available Beat Knechtle,1 Matthias Alexander Zingg,2 Patrizia Knechtle,1 Thomas Rosemann,2 Christoph Alexander Rüst2 1Gesundheitszentrum St Gallen, St Gallen, 2Institute of Primary Care, University of Zurich, Zurich, Switzerland Abstract: Recent studies investigating ultraendurance athletes showed an association between excessive fluid intake and swelling of the lower limbs such as the feet. To date, this association has been investigated in single-stage ultraendurance races, but not in multistage ultraendurance races. In this case study, we investigated a potential association between fluid intake and feet swelling in a multistage ultraendurance race such as a Deca Iron ultratriathlon with ten Ironman triathlons within 10 consecutive days. A 49-year-old well-experienced ultratriathlete competed in autumn 2013 in the Deca Iron ultratriathlon held in Lonata del Garda, Italy, and finished the race as winner within 129:33 hours:minutes. Changes in body mass (including body fat and lean body mass, foot volume, total body water, and laboratory measurements were assessed. Food and fluid intake during rest and competing were recorded, and energy and fluid turnovers were estimated. During the ten stages, the volume of the feet increased, percentage body fat decreased, creatinine and urea levels increased, hematocrit and hemoglobin values decreased, and plasma [Na+] remained unchanged. The increase in foot volume was significantly and positively related to fluid intake during the stages. The poststage volume of the foot was related to poststage total body water, poststage creatinine, and poststage urea. This case report shows that the volume of the foot increased during the ten stages, and the increase in volume was significantly and positively related to fluid intake during the stages. Furthermore, the poststage volume of the foot was related to poststage total body water, poststage creatinine, and poststage urea. The continuous feet swelling during the race was

  15. Particle swarm optimization of ascent trajectories of multistage launch vehicles

    Science.gov (United States)

    Pontani, Mauro

    2014-02-01

    Multistage launch vehicles are commonly employed to place spacecraft and satellites in their operational orbits. If the rocket characteristics are specified, the optimization of its ascending trajectory consists of determining the optimal control law that leads to maximizing the final mass at orbit injection. The numerical solution of a similar problem is not trivial and has been pursued with different methods, for decades. This paper is concerned with an original approach based on the joint use of swarming theory and the necessary conditions for optimality. The particle swarm optimization technique represents a heuristic population-based optimization method inspired by the natural motion of bird flocks. Each individual (or particle) that composes the swarm corresponds to a solution of the problem and is associated with a position and a velocity vector. The formula for velocity updating is the core of the method and is composed of three terms with stochastic weights. As a result, the population migrates toward different regions of the search space taking advantage of the mechanism of information sharing that affects the overall swarm dynamics. At the end of the process the best particle is selected and corresponds to the optimal solution to the problem of interest. In this work the three-dimensional trajectory of the multistage rocket is assumed to be composed of four arcs: (i) first stage propulsion, (ii) second stage propulsion, (iii) coast arc (after release of the second stage), and (iv) third stage propulsion. The Euler-Lagrange equations and the Pontryagin minimum principle, in conjunction with the Weierstrass-Erdmann corner conditions, are employed to express the thrust angles as functions of the adjoint variables conjugate to the dynamics equations. The use of these analytical conditions coming from the calculus of variations leads to obtaining the overall rocket dynamics as a function of seven parameters only, namely the unknown values of the initial state

  16. Mechanical (turbines and auxiliary equipment)

    CERN Document Server

    Sherry, A; Cruddace, AE

    2013-01-01

    Modern Power Station Practice, Volume 3: Mechanical (Turbines and Auxiliary Equipment) focuses on the development of turbines and auxiliary equipment used in power stations in Great Britain. Topics covered include thermodynamics and steam turbine theory; turbine auxiliary systems such as lubrication systems, feed water heating systems, and the condenser and cooling water plants. Miscellaneous station services, and pipework in power plants are also described. This book is comprised of five chapters and begins with an overview of thermodynamics and steam turbine theory, paying particular attenti

  17. Aerodynamic and Performance Behavior of a Three-Stage High Efficiency Turbine at Design and Off-Design Operating Points

    Directory of Open Access Journals (Sweden)

    M. T. Schobeiri

    2004-01-01

    Full Text Available This article deals with the aerodynamic and performance behavior of a three-stage high pressure research turbine with 3-D curved blades at its design and off-design operating points. The research turbine configuration incorporates six rows beginning with a stator row. Interstage aerodynamic measurements were performed at three stations, namely downstream of the first rotor row, the second stator row, and the second rotor row. Interstage radial and circumferential traversing presented a detailed flow picture of the middle stage. Performance measurements were carried out within a rotational speed range of 75% to 116% of the design speed. The experimental investigations have been carried out on the recently established multi-stage turbine research facility at the Turbomachinery Performance and Flow Research Laboratory, TPFL, of Texas A&M University.

  18. Great expectations: large wind turbines

    International Nuclear Information System (INIS)

    De Vries, E.

    2001-01-01

    This article focuses on wind turbine product development, and traces the background to wind turbines from the first generation 1.5 MW machines in 1995-6, plans for the second generation 3-5 MW class turbines to meet the expected boom in offshore wind projects, to the anticipated installation of a 4.5 MW turbine, and offshore wind projects planned for 2000-2002. The switch by the market leader Vestas to variable speed operation in 2000, the new product development and marketing strategy taken by the German Pro + Pro consultancy in their design of a 1.5 MW variable speed pitch control concept, the possible limiting of the size of turbines due to logistical difficulties, opportunities offered by air ships for large turbines, and the commissioning of offshore wind farms are discussed. Details of some 2-5 MW offshore wind turbine design specifications are tabulated

  19. Wind Turbine Blade

    DEFF Research Database (Denmark)

    2010-01-01

    The invention relates to a blade for a wind turbine, particularly to a blade that may be produced by an advanced manufacturing process for producing a blade with high quality structural components. Particularly, the structural components, which are preferably manufactured from fibre reinforced...

  20. Alcoa wind turbines

    Science.gov (United States)

    Ai, D. K.

    1979-01-01

    An overview of Alcoa's wind energy program is given with emphasis on the the development of a low cost, reliable Darrieus Vertical Axis Wind Turbine System. The design layouts and drawings for fabrication are now complete, while fabrication and installation to utilize the design are expected to begin shortly.

  1. Turbine imaging technology assessment

    Energy Technology Data Exchange (ETDEWEB)

    Moursund, R. A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Carlson, T. J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2004-12-01

    The goal of this project was to identify and evaluate imaging technologies for observing juvenile fish within a Kaplan turbine, and specifically that would enable scientists to determine mechanisms of fish injury within an operating turbine unit. This report documents the opportunities and constraints for observing juvenile fish at specific locations during turbine passage. These observations were used to make modifications to dam structures and operations to improve conditions for fish passage while maintaining or improving hydropower production. The physical and hydraulic environment that fish experience as they pass through the hydroelectric plants were studied and the regions with the greatest potential for injury were defined. Biological response data were also studied to determine the probable types of injuries sustained in the turbine intake and what types of injuries are detectable with imaging technologies. The study grouped injury-causing mechanisms into two categories: fluid (pressure/cavitation, shear, turbulence) and mechanical (strike/collision, grinding/pinching, scraping). The physical constraints of the environment, together with the likely types of injuries to fish, provided the parameters needed for a rigorous imaging technology evaluation. Types of technology evaluated included both tracking and imaging systems using acoustic technologies (such as sonar and acoustic tags) and optic technologies (such as pulsed-laser videography, which is high-speed videography using a laser as the flash). Criteria for determining image data quality such as frame rate, target detectability, and resolution were used to quantify the minimum requirements of an imaging sensor.

  2. Small hydraulic turbine drives

    Science.gov (United States)

    Rostafinski, W. A.

    1970-01-01

    Turbine, driven by the fluid being pumped, requires no external controls, is completely integrated into the flow system, and has bearings which utilize the main fluid for lubrication and cooling. Torque capabilities compare favorably with those developed by positive displacement hydraulic motors.

  3. Gas turbine drives

    Energy Technology Data Exchange (ETDEWEB)

    1981-01-01

    Developments in gas turbine drives are reviewed, e.g., low weight per unit power and thrust-weight ratio, fast availability of the maximum speed, absolute resistance to cold and to droplet formation vibrationeless run, and low exhaust gas temperatures. Applications in aeronautic engineering (turbofan), power stations, marine propulsion systems, railways and road transportation vehicles are mentioned.

  4. Gas turbine electric generator

    International Nuclear Information System (INIS)

    Nemoto, Masaaki; Yuhara, Tetsuo.

    1993-01-01

    When troubles are caused to a boundary of a gas turbine electric generator, there is a danger that water as an operation medium for secondary circuits leaks to primary circuits, to stop a plant and the plant itself can not resume. Then in the present invention, helium gases are used as the operation medium not only for the primary circuits but also for the secondary circuits, to provide so-called a direct cycle gas turbine system. Further, the operation media of the primary and secondary circuits are recycled by a compressor driven by a primary circuit gas turbine, and the turbine/compressor is supported by helium gas bearings. Then, problems of leakage of oil and water from the bearings or the secondary circuits can be solved, further, the cooling device in the secondary circuit is constituted as a triple-walled tube structure by way of helium gas, to prevent direct leakage of coolants into the reactor core even if cracks are formed to pipes. (N.H.)

  5. Integrated turbine bypass system

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, L.H.; Dickenson, R.J.; Parry, W.T.; Retzlaff, K.M.

    1982-07-01

    Turbine steam-flow bypasses have been used for years in various sizes and applications. Because of differing system requirements, their use has been more predominant in Europe than in the United States. Recently, some utilities and consulting engineers have been re-evaluating their need for various types of bypass operation in fossil-fuelled power plants.

  6. Floating offshore turbines

    DEFF Research Database (Denmark)

    Tande, John Olav Giæver; Merz, Karl; Schmidt Paulsen, Uwe

    2014-01-01

    metric of energy production per unit steel mass. Floating offshore wind turbines represent a promising technology. The successful operation of HyWind and WindFloat in full scale demonstrates a well advanced technology readiness level, where further development will go into refining the concepts, cost...

  7. Radial gas turbine design

    Energy Technology Data Exchange (ETDEWEB)

    Krausche, S.; Ohlsson, Johan

    1998-04-01

    The objective of this work was to develop a program dealing with design point calculations of radial turbine machinery, including both compressor and turbine, with as few input data as possible. Some simple stress calculations and turbine metal blade temperatures were also included. This program was then implanted in a German thermodynamics program, Gasturb, a program calculating design and off-design performance of gas turbines. The calculations proceed with a lot of assumptions, necessary to finish the task, concerning pressure losses, velocity distribution, blockage, etc., and have been correlated with empirical data from VAT. Most of these values could have been input data, but to prevent the user of the program from drowning in input values, they are set as default values in the program code. The output data consist of geometry, Mach numbers, predicted component efficiency etc., and a number of graphical plots of geometry and velocity triangles. For the cases examined, the error in predicted efficiency level was within {+-} 1-2% points, and quite satisfactory errors in geometrical and thermodynamic conditions were obtained Examination paper. 18 refs, 36 figs

  8. Wind turbine state estimation

    DEFF Research Database (Denmark)

    Knudsen, Torben

    2014-01-01

    Dynamic inflow is an effect which is normally not included in the models used for wind turbine control design. Therefore, potential improvement from including this effect exists. The objective in this project is to improve the methods previously developed for this and especially to verify the res...

  9. NDDP multi-stage flash desalination process simulator design

    International Nuclear Information System (INIS)

    Chatterjee, M.; Sashi Kumar, G.N.; Mahendra, A.K.; Sanyal, A.; Gouthaman, G.

    2006-05-01

    A majority of large-scale desalination plants all over the world employ multi-stage flash (MSF) distillation process. Many of these MSF desalination plants have been set up near to nuclear power plants (generally called as nuclear desalination plants) to effectively utilize the low-grade steam from the power plants as the source of energy. A computer program called MSFSIM has been developed to simulate the MSF desalination plant operation both for steady state and various transients including start up. This code predicts the effect of number of stages, flashing temperature, velocity of brine flowing through the tubes of brine heater and evaporators, temperature of the condensing thin film etc. on the plant performance ratio. Such a code can be used for the design of a new plant and to predict its operating and startup characteristics. The code has been extensively validated with available start up data from the pilot MSF desalination plant of 425-m3/day capacity at Trombay, Mumbai. A MSF desalination plant of 4500-m3/day capacity is under construction by BARC at Kalpakkam, which will utilize the steam from Madras Atomic Power Station (MAPS). In this present work extensive parametric study of the 4500-m3/day capacity desalination plant at Kalpakkam has been done using the code MSFSIM for optimizing the operating parameters in order to maximize the performance ratio for stable plant operation. The aim of the work is prediction of plant performance under different operating conditions. (author)

  10. Design procedure of capsule with multistage heater control (named MUSTAC)

    International Nuclear Information System (INIS)

    Someya, Hiroyuki; Endoh, Yasuichi; Hoshiya, Taiji; Niimi, Motoji; Harayama, Yasuo

    1990-11-01

    A capsule with electric heaters at multistage (named MUSTAC) is a type of capsule used in JMTR. The heaters are assembled in the capsule. Supply electric current to the heaters can be independently adjusted with a control systems that keeps irradiation specimens to constant temperature. The capsule being used, the irradiation specimen are inserted into specimen holders. Gas-gap size, between outer surface of specimen holders and inner surface of capsule casing, is calculated and determined to be flatten temperature of loaded specimens over the region. The rise or drop of specimen temperature in accordance with reactor power fluctuations is corrected within the target temperature of specimen by using the heaters filled into groove at specimen holder surface. The present report attempts to propose a reasonable design procedure of the capsules by means of compiling experience for designs, works and irradiation data of the capsules and to prepare for useful informations against onward capsule design. The key point of the capsule lies on thermal design. Now design thermal calculations are complicated in case of specimen holder with multihole. Resolving these issues, it is considered from new on that an emphasis have to placed on settling a thermal calculation device, for an example, a computer program on calculation specimen temperature. (author)

  11. ''Theta gun,'' a multistage, coaxial, magnetic induction projectile accelerator

    International Nuclear Information System (INIS)

    Burgess, T.J.; Duggin, B.W.; Cowan, M. Jr.

    1985-11-01

    We experimentally and theoretically studied a multistage coaxial magnetic induction projectile accelerator. We call this system a ''theta gun'' to differentiate it from other coaxial accelerator concepts such as the mass driver. We conclude that this system can theoretically attain railgun performance only for large caliber or very high injection velocity and, even then, only for long coil geometry. Our experiments with a three-stage, capactor bank-driven accelerator are described. The experiments are modeled with a 1-1/2 dimensional equivalent circuit-hydrodynamics code which is also described. We derive an expression for the conditions of coaxial accelerator-railgun ''velocity breakeven'' in the absence of ohmic and hydrodynamic effects. This, in conjunction with an expression for the magnetic coupling coefficient, defines a set of geometric relations which the coaxial system must simultaneously satisfy. Conclusions concerning both the existence and configuration of a breakeven coaxial system follow from this requirement. The relative advantages and disadvantages of the coaxial induction projectile accelerator, previously cited in the literature, are critiqued from the viewpoint of our analysis and experimental results. We find that the advantages vis-a-vis the railgun have been overstated. 13 refs., 17 figs

  12. Synthetic Multiple-Imputation Procedure for Multistage Complex Samples

    Directory of Open Access Journals (Sweden)

    Zhou Hanzhi

    2016-03-01

    Full Text Available Multiple imputation (MI is commonly used when item-level missing data are present. However, MI requires that survey design information be built into the imputation models. For multistage stratified clustered designs, this requires dummy variables to represent strata as well as primary sampling units (PSUs nested within each stratum in the imputation model. Such a modeling strategy is not only operationally burdensome but also inferentially inefficient when there are many strata in the sample design. Complexity only increases when sampling weights need to be modeled. This article develops a generalpurpose analytic strategy for population inference from complex sample designs with item-level missingness. In a simulation study, the proposed procedures demonstrate efficient estimation and good coverage properties. We also consider an application to accommodate missing body mass index (BMI data in the analysis of BMI percentiles using National Health and Nutrition Examination Survey (NHANES III data. We argue that the proposed methods offer an easy-to-implement solution to problems that are not well-handled by current MI techniques. Note that, while the proposed method borrows from the MI framework to develop its inferential methods, it is not designed as an alternative strategy to release multiply imputed datasets for complex sample design data, but rather as an analytic strategy in and of itself.

  13. Multistage principal component analysis based method for abdominal ECG decomposition

    International Nuclear Information System (INIS)

    Petrolis, Robertas; Krisciukaitis, Algimantas; Gintautas, Vladas

    2015-01-01

    Reflection of fetal heart electrical activity is present in registered abdominal ECG signals. However this signal component has noticeably less energy than concurrent signals, especially maternal ECG. Therefore traditionally recommended independent component analysis, fails to separate these two ECG signals. Multistage principal component analysis (PCA) is proposed for step-by-step extraction of abdominal ECG signal components. Truncated representation and subsequent subtraction of cardio cycles of maternal ECG are the first steps. The energy of fetal ECG component then becomes comparable or even exceeds energy of other components in the remaining signal. Second stage PCA concentrates energy of the sought signal in one principal component assuring its maximal amplitude regardless to the orientation of the fetus in multilead recordings. Third stage PCA is performed on signal excerpts representing detected fetal heart beats in aim to perform their truncated representation reconstructing their shape for further analysis. The algorithm was tested with PhysioNet Challenge 2013 signals and signals recorded in the Department of Obstetrics and Gynecology, Lithuanian University of Health Sciences. Results of our method in PhysioNet Challenge 2013 on open data set were: average score: 341.503 bpm 2 and 32.81 ms. (paper)

  14. Multi-stage low-pressure avalanche chamber

    International Nuclear Information System (INIS)

    Zanevskij, Yu.V.; Peshekhonov, V.D.; Smykov, L.P.

    1985-01-01

    A multi-stage avalanche-chamber filled with isobutane operating at the pressure of 6 torr is described. The chamber comprises an amplifying gap, drift gap and multiwire proportional chamber with interelectrode gaps equal to 4 mm. The anode plane of the proportional chamber is winded of wire 2 μm in diameter with 2 mm pitch. The cathode are winded orthogonally to anode wires of wire 50 μm in diameter with 1 mm pitch. Drift and preamplifier gaps are formed by grid electrodes made of wire 50 μm in diameter with dimension of the cell equal to 1x1 mm. Width of the drift gap is 5 mm, width of the preamplification gap is 3 or 9 mm. Coordinate data are removed from the cathodes of the proportional chamber by means of delay lines. Sensitive square of the chamber equals 240x180 mm. Gas gain coefficient is 3x10 6 at its square nonuniformity equal to approximately 3%. Spatial resolution by both coordinates equals 170 μm; spatial resolution for isotropic α-emitters located close to the preamplifier gap is equal to 500 μm

  15. Product analysis of catalytic multi-stage hydropyrolysis of lignite

    Energy Technology Data Exchange (ETDEWEB)

    Wen Li; Na Wang; Baoqing Li [Chinese Academy of Science, Taiyuan (China). State Key Lab of Coal Conversion, Institute of Coal Chemistry

    2003-03-01

    A lignite added with 0.2% MoS{sub 2} as catalyst was pyrolyzed under H{sub 2} using multi-stage heating method (MHyPy) which means holding a suitable time near the peak temperature. The product distribution and detailed analysis of products were performed. The results show that the tar yield increased to 63.9% during MHyPy compared with that of 51.8% in traditional hydropyrolysis (HyPy), while the gas yield decreased to a half. This suggests the effective utilization of hydrogen during MHyPy. The light aromatics in the tar from MHyPy increased remarkably 42, 37.8 and 115.4% for BTX, PCX and naphthalenes, respectively. Biphenyls were also observed in the tar from MHyPy, which indicated the effective hydrogenation occurs during catalytic MHyPy. The rich pore structure of the char from MHyPy hints its high reactivity in the subsequent conversion process such as gasification and combustion. 15 refs., 7 figs., 2 tabs.

  16. Product analysis of catalytic multi-stage hydropyrolysis of coal

    Energy Technology Data Exchange (ETDEWEB)

    Li, W.; Wang, N.; Li, B. [Chinese Academy of Sciences, Taiyuan (China). State Key Lab. of Coal Conversion

    2002-05-01

    Multi-stage hydropyrolysis (MHyPy) and hydropyrolysis (HyPy) of Xundian lignite, with MoS{sub 2} as the catalyst, were performed in a fixed bed reactor. The product distribution and property were investigated in detail. The results show that the tar yield increases to 63.9% during MHyPy compared with that of 51.8% in HyPy, while the gas yield decreases by 50%. The tar composition does not make big difference between MHyPy and HyPy. However, the light aromatics in the tar from MHyPy increase remarkably by 42%, 37.8% and 115.4% for BTX, PCX and naphthalene respectively. The specific surface area of char from MHyPy is larger than that from HyPy. The average pore diameter of char from MHyPy is smaller than that from HyPy, while the pore volume increases by 100% compared with that from HyPy. The catalytic MHyPy has an obvious advantage over HyPy. 10 refs., 8 figs., 3 tabs.

  17. Computer Adaptive Multistage Testing: Practical Issues, Challenges and Principles

    Directory of Open Access Journals (Sweden)

    Halil Ibrahim SARI

    2016-12-01

    Full Text Available The purpose of many test in the educational and psychological measurement is to measure test takers’ latent trait scores from responses given to a set of items. Over the years, this has been done by traditional methods (paper and pencil tests. However, compared to other test administration models (e.g., adaptive testing, traditional methods are extensively criticized in terms of producing low measurement accuracy and long test length. Adaptive testing has been proposed to overcome these problems. There are two popular adaptive testing approaches. These are computerized adaptive testing (CAT and computer adaptive multistage testing (ca-MST. The former is a well-known approach that has been predominantly used in this field. We believe that researchers and practitioners are fairly familiar with many aspects of CAT because it has more than a hundred years of history. However, the same thing is not true for the latter one. Since ca-MST is relatively new, many researchers are not familiar with features of it. The purpose of this study is to closely examine the characteristics of ca-MST, including its working principle, the adaptation procedure called the routing method, test assembly, and scoring, and provide an overview to researchers, with the aim of drawing researchers’ attention to ca-MST and encouraging them to contribute to the research in this area. The books, software and future work for ca-MST are also discussed.

  18. A multistage framework for dismount spectral verification in the VNIR

    Science.gov (United States)

    Rosario, Dalton

    2013-05-01

    A multistage algorithm suite is proposed for a specific target detection/verification scenario, where a visible/near infrared hyperspectral (HS) sample is assumed to be available as the only cue from a reference image frame. The target is a suspicious dismount. The suite first applies a biometric based human skin detector to focus the attention of the search. Using as reference all of the bands in the spectral cue, the suite follows with a Bayesian Lasso inference stage designed to isolate pixels representing the specific material type cued by the user and worn by the human target (e.g., hat, jacket). In essence, the search focuses on testing material types near skin pixels. The third stage imposes an additional constraint through RGB color quantization and distance metric checking, limiting even further the search for material types in the scene having visible color similar to the target visible color. Using the proposed cumulative evidence strategy produced some encouraging range-invariant results on real HS imagery, dramatically reducing to zero the false alarm rate on the example dataset. These results were in contrast to the results independently produced by each one of the suite's stages, as the spatial areas of each stage's high false alarm outcome were mutually exclusive in the imagery. These conclusions also apply to results produced by other standard methods, in particular the kernel SVDD (support vector data description) and matched filter, as shown in the paper.

  19. A cascaded three-phase symmetrical multistage voltage multiplier

    International Nuclear Information System (INIS)

    Iqbal, Shahid; Singh, G K; Besar, R; Muhammad, G

    2006-01-01

    A cascaded three-phase symmetrical multistage Cockcroft-Walton voltage multiplier (CW-VM) is proposed in this report. It consists of three single-phase symmetrical voltage multipliers, which are connected in series at their smoothing columns like string of batteries and are driven by three-phase ac power source. The smoothing column of each voltage multiplier is charged twice every cycle independently by respective oscillating columns and discharged in series through load. The charging discharging process completes six times a cycle and therefore the output voltage ripple's frequency is of sixth order of the drive signal frequency. Thus the proposed approach eliminates the first five harmonic components of load generated voltage ripples and sixth harmonic is the major ripple component. The proposed cascaded three-phase symmetrical voltage multiplier has less than half the voltage ripple, and three times larger output voltage and output power than the conventional single-phase symmetrical CW-VM. Experimental and simulation results of the laboratory prototype are given to show the feasibility of proposed cascaded three-phase symmetrical CW-VM

  20. Coexistence of mitochondrial 12S rRNA C1494T and CO1/tRNASer(UCN) G7444A mutations in two Han Chinese pedigrees with aminoglycoside-induced and non-syndromic hearing loss

    International Nuclear Information System (INIS)

    Yuan Huijun; Chen Jing; Liu Xin; Cheng Jing; Wang Xinjian; Yang Li; Yang Shuzhi; Cao Juyang; Kang Dongyang; Dai Pu; Zha, Suoqiang; Han Dongyi; Young Wieyen; Guan Minxin

    2007-01-01

    Mutations in mitochondrial DNA are one of the important causes of hearing loss. We report here the clinical, genetic, and molecular characterization of two Han Chinese pedigrees with maternally transmitted aminoglycoside-induced and nonsyndromic bilateral hearing loss. Clinical evaluation revealed the wide range of severity, age-at-onset, and audiometric configuration of hearing impairment in matrilineal relatives in these families. The penetrances of hearing loss in these pedigrees were 20% and 18%, when aminoglycoside-induced deafness was included. When the effect of aminoglycosides was excluded, the penetrances of hearing loss in these seven pedigrees were 10% and 15%. Sequence analysis of the complete mitochondrial genomes in these pedigrees showed the presence of the deafness-associated 12S rRNA C1494T and CO1/tRNA Ser(UCN) G7444A mutations. Their distinct sets of mtDNA polymorphism belonged to Eastern Asian haplogroup C4a1, while other previously identified six Chinese mitochondrial genomes harboring the C1494T mutation belong to haplogroups D5a2, D, R, and F1, respectively. This suggested that the C1494T or G7444A mutation occurred sporadically and multiplied through evolution of the mitochondrial DNA (mtDNA). The absence of functionally significant mutations in tRNA and rRNAs or secondary LHON mutations in their mtDNA suggest that these mtDNA haplogroup-specific variants may not play an important role in the phenotypic expression of the 12S rRNA C1494T and CO1/tRNA Ser(UCN) G7444A mutations in those Chinese families. However, aminoglycosides and other nuclear modifier genes play a modifying role in the phenotypic manifestation of the C1494T mutation in these Chinese families

  1. An investigation of rotor tip leakage flows in the rear-block of a multistage compressor

    Science.gov (United States)

    Brossman, John Richard

    An effective method to improve gas turbine propulsive efficiency is to increase the bypass ratio. With fan diameter reaching a practical limit, increases in bypass ratio can be obtained from reduced core engine size. Decreasing the engine core, results in small, high pressure compressor blading, and large relative tip clearances. At general rule of 1% reduction in compressor efficiency with a 1% increase in tip clearance, a 0.66% change in SFC indicates the entire engine is sensitive to high pressure compressor tip leakage flows. Therefore, further investigations and understanding of the rotor tip leakage flows can help to improve gas turbine engine efficiency. The objectives of this research were to investigate tip leakage flows through computational modeling, examine the baseline experimental steady-stage performance, and acquire unsteady static pressure, over-the rotor to observe the tip leakage flow structure. While tip leakage flows have been investigated in the past, there have been no facilities capable of matching engine representative Reynolds number and Mach number while maintaining blade row interactions, presenting a unique and original flow field to investigate at the Purdue 3-stage axial compressor facility. To aid the design of experimental hardware and determine the influence of clearance geometry on compressor performance, a computational model of the Purdue 3-stage compressor was investigated using a steady RANS CFD analysis. A cropped rotor and casing recess design was investigated to increase the rotor tip clearance. While there were small performance differences between the geometries, the tip leakage flow field was found independent of the design therefore designing future experimental hardware around a casing recess is valid. The largest clearance with flow margin past the design point was 4% tip clearance based on the computational model. The Purdue 3-stage axial compressor facility was rebuilt and setup for high quality, detailed flow

  2. STYLE, Steam Cycle Heat Balance for Turbine Blade Design in Marine Operation

    International Nuclear Information System (INIS)

    Love, J.B.; Dines, W.R.

    1970-01-01

    1 - Nature of physical problem solved: The programme carries out iterative steam cycle heat balance calculations for a wide variety of steam cycles including single reheat, live steam reheat and multistage moisture separation. Facilities are also available for including the steam-consuming auxiliaries associated with a marine installation. Though no attempt is made to carry out a detailed turbine blading design the programme is capable of automatically varying the blading efficiency from stage to stage according to local steam volume flow rate, dryness fraction and shaft speed. 2 - Method of solution: 3 - Restrictions on the complexity of the problem: Steam pressures to lie within range 0.2 to 5,000 lb/square inch abs steam temperatures to lie within range 50 to 1600 degrees F. Not more than 40 points per turbine expansion line; Not more than 10 expansion lines; Not more than 15 feed heaters. UNIVAC 1108 version received from FIAT Energia Nucleare, Torino, Italy

  3. Water turbine technology for small power stations

    Science.gov (United States)

    Salovaara, T.

    1980-02-01

    The paper examines hydro-power stations and the efficiency and costs of using water turbines to run them. Attention is given to different turbine types emphasizing the use of Kaplan-turbines and runners. Hydraulic characteristics and mechanical properties of low head turbines and small turbines, constructed of fully fabricated steel plate structures, are presented.

  4. Multistage Effort and the Equity Structure of Venture Investment Based on Reciprocity Motivation

    OpenAIRE

    Ding, Chuan; Chen, Jiacheng; Liu, Xin; Zheng, Junjun

    2015-01-01

    For venture capitals, it is a long process from an entry to its exit. In this paper, the activity of venture investment will be divided into multistages. And, according to the effort level entrepreneurs will choose, the venture capitalists will provide an equity structure at the very beginning. As a benchmark for comparison, we will establish two game models on multistage investment under perfect rationality: a cooperative game model and a noncooperative one. Further, as a cause of pervasive ...

  5. SMART POWER TURBINE

    Energy Technology Data Exchange (ETDEWEB)

    Nirm V. Nirmalan

    2003-11-01

    Gas turbines are the choice technology for high-performance power generation and are employed in both simple and combined cycle configurations around the world. The Smart Power Turbine (SPT) program has developed new technologies that are needed to further extend the performance and economic attractiveness of gas turbines for power generation. Today's power generation gas turbines control firing temperatures indirectly, by measuring the exhaust gas temperature and then mathematically calculating the peak combustor temperatures. But temperatures in the turbine hot gas path vary a great deal, making it difficult to control firing temperatures precisely enough to achieve optimal performance. Similarly, there is no current way to assess deterioration of turbine hot-gas-path components without shutting down the turbine. Consequently, maintenance and component replacements are often scheduled according to conservative design practices based on historical fleet-averaged data. Since fuel heating values vary with the prevalent natural gas fuel, the inability to measure heating value directly, with sufficient accuracy and timeliness, can lead to maintenance and operational decisions that are less than optimal. GE Global Research Center, under this Smart Power Turbine program, has developed a suite of novel sensors that would measure combustor flame temperature, online fuel lower heating value (LHV), and hot-gas-path component life directly. The feasibility of using the ratio of the integrated intensities of portions of the OH emission band to determine the specific average temperature of a premixed methane or natural-gas-fueled combustion flame was demonstrated. The temperature determined is the temperature of the plasma included in the field of view of the sensor. Two sensor types were investigated: the first used a low-resolution fiber optic spectrometer; the second was a SiC dual photodiode chip. Both methods worked. Sensitivity to flame temperature changes was

  6. Turbine repair process, repaired coating, and repaired turbine component

    Science.gov (United States)

    Das, Rupak; Delvaux, John McConnell; Garcia-Crespo, Andres Jose

    2015-11-03

    A turbine repair process, a repaired coating, and a repaired turbine component are disclosed. The turbine repair process includes providing a turbine component having a higher-pressure region and a lower-pressure region, introducing particles into the higher-pressure region, and at least partially repairing an opening between the higher-pressure region and the lower-pressure region with at least one of the particles to form a repaired turbine component. The repaired coating includes a silicon material, a ceramic matrix composite material, and a repaired region having the silicon material deposited on and surrounded by the ceramic matrix composite material. The repaired turbine component a ceramic matrix composite layer and a repaired region having silicon material deposited on and surrounded by the ceramic matrix composite material.

  7. Multi-Stage Recognition of Speech Emotion Using Sequential Forward Feature Selection

    Directory of Open Access Journals (Sweden)

    Liogienė Tatjana

    2016-07-01

    Full Text Available The intensive research of speech emotion recognition introduced a huge collection of speech emotion features. Large feature sets complicate the speech emotion recognition task. Among various feature selection and transformation techniques for one-stage classification, multiple classifier systems were proposed. The main idea of multiple classifiers is to arrange the emotion classification process in stages. Besides parallel and serial cases, the hierarchical arrangement of multi-stage classification is most widely used for speech emotion recognition. In this paper, we present a sequential-forward-feature-selection-based multi-stage classification scheme. The Sequential Forward Selection (SFS and Sequential Floating Forward Selection (SFFS techniques were employed for every stage of the multi-stage classification scheme. Experimental testing of the proposed scheme was performed using the German and Lithuanian emotional speech datasets. Sequential-feature-selection-based multi-stage classification outperformed the single-stage scheme by 12–42 % for different emotion sets. The multi-stage scheme has shown higher robustness to the growth of emotion set. The decrease in recognition rate with the increase in emotion set for multi-stage scheme was lower by 10–20 % in comparison with the single-stage case. Differences in SFS and SFFS employment for feature selection were negligible.

  8. Comprehensive study for Anammox process via multistage anaerobic baffled reactors

    Science.gov (United States)

    Ismail, Sherif; Tawfik, Ahmed

    2017-11-01

    Continuous anaerobic ammonia oxidation (Anammox) process in multistage anaerobic baffled (MABR) reactor was investigated. The reactor was operated for approximately 150 days at constant hydraulic retention time (HRT) of 48 h and was fed with synthetic wastewater containing nitrite and ammonium as main substrates. The MABR was inoculated with mixed culture bacteria collected from activated sludge plant (41.6 g MLSS/L and 19.1 g MLVSS/L). The MABR reactor exhibited excellent performance for the start-up of Anammox process within a period of 35 days. The start-up period was divided into four successive phases; cell lysis, lag, activity elevation and steady state. Total inorganic nitrogen (TIN) removal efficiency of 96.8± 0.9% was achieved at steady state conditions, corresponding to nitrogen removal rate (NRR) of 50.2±1.7 mg N/L·d. Moreover, the effect of HRT on the Anammox process was assessed with applying five different HRTs of (48, 38.4, 28.8, 19.2 and 9.6 h). Decreasing HRT from 48 to 9.6 h reduced the removal efficiencies of NH4-N, NO2-N and TIN from 97.7±2.2 to 49.0±9.8%, from 95.7±1.9 to 71.0±8.5% and from 96.8±0.9 to 57.9±9.1%, respectively, that corresponding to reduction in NRR from 50.8±1.2 mg N/L·d at HRT of 48 h to 32.5±5.0 mg N/L·d at HRT of 9.6 h.

  9. Advanced Hydrogen Turbine Development

    Energy Technology Data Exchange (ETDEWEB)

    Marra, John [Siemens Energy, Inc., Orlando, FL (United States)

    2015-09-30

    Under the sponsorship of the U.S. Department of Energy (DOE) National Energy Technology Laboratories, Siemens has completed the Advanced Hydrogen Turbine Development Program to develop an advanced gas turbine for incorporation into future coal-based Integrated Gasification Combined Cycle (IGCC) plants. All the scheduled DOE Milestones were completed and significant technical progress was made in the development of new technologies and concepts. Advanced computer simulations and modeling, as well as subscale, full scale laboratory, rig and engine testing were utilized to evaluate and select concepts for further development. Program Requirements of: A 3 to 5 percentage point improvement in overall plant combined cycle efficiency when compared to the reference baseline plant; 20 to 30 percent reduction in overall plant capital cost when compared to the reference baseline plant; and NOx emissions of 2 PPM out of the stack. were all met. The program was completed on schedule and within the allotted budget

  10. Probabilistic Design of Wind Turbines

    DEFF Research Database (Denmark)

    Toft, Henrik Stensgaard

    During the last decades, wind turbines have been continuously developed with the aim of maximizing the life cycle benefits (production of electricity) minus the costs of planning, materials, installation, operation & maintenance as well as possible failure. In order to continue this development...... turbines and the central topics considered are statistical load extrapolation of extreme loads during operation and reliability assessment of wind turbine blades. Wind turbines differ from most civil engineering structures by having a control system which highly influences the loading. In the literature......, methods for estimating the extreme load-effects on a wind turbine during operation, where the control system is active, have been proposed. But these methods and thereby the estimated loads are often subjected to a significant uncertainty which influences the reliability of the wind turbine...

  11. Reliability Analysis of Wind Turbines

    DEFF Research Database (Denmark)

    Toft, Henrik Stensgaard; Sørensen, John Dalsgaard

    2008-01-01

    In order to minimise the total expected life-cycle costs of a wind turbine it is important to estimate the reliability level for all components in the wind turbine. This paper deals with reliability analysis for the tower and blades of onshore wind turbines placed in a wind farm. The limit states...... consideres are in the ultimate limit state (ULS) extreme conditions in the standstill position and extreme conditions during operating. For wind turbines, where the magnitude of the loads is influenced by the control system, the ultimate limit state can occur in both cases. In the fatigue limit state (FLS......) the reliability level for a wind turbine placed in a wind farm is considered, and wake effects from neighbouring wind turbines is taken into account. An illustrative example with calculation of the reliability for mudline bending of the tower is considered. In the example the design is determined according...

  12. Steam turbines for the future

    International Nuclear Information System (INIS)

    Trassl, W.

    1988-01-01

    Approximately 75% of the electrical energy produced in the world is generated in power plants with steam turbines (fossil and nuclear). Although gas turbines are increasingly applied in combined cycle power plants, not much will change in this matter in the future. As far as the steam parameters and the maximum unit output are concerned, a certain consolidation was noted during the past decades. The standard of development and mathematical penetration of the various steam turbine components is very high today and is applied in the entire field: For saturated steam turbines in nuclear power plants and for steam turbines without reheat, with reheat and with double reheat in fossil-fired power plants and for steam turbines with and without reheat in combined cycle power plants. (orig.) [de

  13. Wind Turbine Providing Grid Support

    DEFF Research Database (Denmark)

    2011-01-01

    changing the operation of the wind turbine to a more efficient working point.; When the rotational speed of the rotor reaches a minimum value, the wind turbine enters a recovery period to re-accelerate the rotor to the nominal rotational speed while further contributing to the stability of the electrical......A variable speed wind turbine is arranged to provide additional electrical power to counteract non-periodic disturbances in an electrical grid. A controller monitors events indicating a need to increase the electrical output power from the wind turbine to the electrical grid. The controller...... is arranged to control the wind turbine as follows: after an indicating event has been detected, the wind turbine enters an overproduction period in which the electrical output power is increased, wherein the additional electrical output power is taken from kinetic energy stored in the rotor and without...

  14. Superconducting wind turbine generators

    International Nuclear Information System (INIS)

    Abrahamsen, A B; Seiler, E; Zirngibl, T; Andersen, N H; Mijatovic, N; Traeholt, C; Pedersen, N F; Oestergaard, J; Noergaard, P B

    2010-01-01

    We have examined the potential of 10 MW superconducting direct drive generators to enter the European offshore wind power market and estimated that the production of about 1200 superconducting turbines until 2030 would correspond to 10% of the EU offshore market. The expected properties of future offshore turbines of 8 and 10 MW have been determined from an up-scaling of an existing 5 MW turbine and the necessary properties of the superconducting drive train are discussed. We have found that the absence of the gear box is the main benefit and the reduced weight and size is secondary. However, the main challenge of the superconducting direct drive technology is to prove that the reliability is superior to the alternative drive trains based on gearboxes or permanent magnets. A strategy of successive testing of superconducting direct drive trains in real wind turbines of 10 kW, 100 kW, 1 MW and 10 MW is suggested to secure the accumulation of reliability experience. Finally, the quantities of high temperature superconducting tape needed for a 10 kW and an extreme high field 10 MW generator are found to be 7.5 km and 1500 km, respectively. A more realistic estimate is 200-300 km of tape per 10 MW generator and it is concluded that the present production capacity of coated conductors must be increased by a factor of 36 by 2020, resulting in a ten times lower price of the tape in order to reach a realistic price level for the superconducting drive train.

  15. Gas turbine premixing systems

    Science.gov (United States)

    Kraemer, Gilbert Otto; Varatharajan, Balachandar; Evulet, Andrei Tristan; Yilmaz, Ertan; Lacy, Benjamin Paul

    2013-12-31

    Methods and systems are provided for premixing combustion fuel and air within gas turbines. In one embodiment, a combustor includes an upstream mixing panel configured to direct compressed air and combustion fuel through premixing zone to form a fuel-air mixture. The combustor includes a downstream mixing panel configured to mix additional combustion fuel with the fule-air mixture to form a combustion mixture.

  16. Airfoils for wind turbine

    Science.gov (United States)

    Tangler, James L.; Somers, Dan M.

    1996-01-01

    Airfoils for the blade of a wind turbine wherein each airfoil is characterized by a thickness in a range from 16%-24% and a maximum lift coefficient designed to be largely insensitive to roughness effects. The airfoils include a family of airfoils for a blade 15 to 25 meters in length, a family of airfoils for a blade 1 to 5 meters in length, and a family of airfoils for a blade 5 to 10 meters in length.

  17. Air Turbines for Wave Energy Conversion

    Directory of Open Access Journals (Sweden)

    Manabu Takao

    2012-01-01

    Full Text Available This paper describes the present status of the art on air turbines, which could be used for wave energy conversion. The air turbines included in the paper are as follows: Wells type turbines, impulse turbines, radial turbines, cross-flow turbine, and Savonius turbine. The overall performances of the turbines under irregular wave conditions, which typically occur in the sea, have been compared by numerical simulation and sea trial. As a result, under irregular wave conditions it is found that the running and starting characteristics of the impulse type turbines could be superior to those of the Wells turbine. Moreover, as the current challenge on turbine technology, the authors explain a twin-impulse turbine topology for wave energy conversion.

  18. Introduction to wind turbine aerodynamics

    CERN Document Server

    Schaffarczyk, Alois Peter

    2014-01-01

    Wind-Turbine Aerodynamics is a self-contained textbook which shows how to come from the basics of fluid mechanics to modern wind turbine blade design. It presents a fundamentals of fluid dynamics and inflow conditions, and gives a extensive introduction into theories describing the aerodynamics of wind turbines. After introducing experiments the book applies the knowledge to explore the impact on blade design.The book is an introduction for professionals and students of very varying levels.

  19. Tornado type wind turbines

    Science.gov (United States)

    Hsu, Cheng-Ting

    1984-01-01

    A tornado type wind turbine has a vertically disposed wind collecting tower with spaced apart inner and outer walls and a central bore. The upper end of the tower is open while the lower end of the structure is in communication with a wind intake chamber. An opening in the wind chamber is positioned over a turbine which is in driving communication with an electrical generator. An opening between the inner and outer walls at the lower end of the tower permits radially flowing air to enter the space between the inner and outer walls while a vertically disposed opening in the wind collecting tower permits tangentially flowing air to enter the central bore. A porous portion of the inner wall permits the radially flowing air to interact with the tangentially flowing air so as to create an intensified vortex flow which exits out of the top opening of the tower so as to create a low pressure core and thus draw air through the opening of the wind intake chamber so as to drive the turbine.

  20. Power turbine ventilation system

    Science.gov (United States)

    Wakeman, Thomas G. (Inventor); Brown, Richard W. (Inventor)

    1991-01-01

    Air control mechanism within a power turbine section of a gas turbine engine. The power turbine section includes a rotor and at least one variable pitch propulsor blade. The propulsor blade is coupled to and extends radially outwardly of the rotor. A first annular fairing is rotatable with the propulsor blade and interposed between the propulsor blade and the rotor. A second fairing is located longitudinally adjacent to the first fairing. The first fairing and the second fairing are differentially rotatable. The air control mechanism includes a platform fixedly coupled to a radially inner end of the propulsor blade. The platform is generally positioned in a first opening and a first fairing. The platform and the first fairing define an outer space. In a first position corresponding with a first propulsor blade pitch, the platform is substantially conformal with the first fairing. In a second position corresponding with the second propulsor blade pitch, an edge portion of the platform is displaced radially outwardly from the first fairing. When the blades are in the second position and rotating about the engine axis, the displacement of the edge portion with respect to the first fairing allows air to flow from the outer space to the annular cavity.

  1. Composite wind turbine towers

    Energy Technology Data Exchange (ETDEWEB)

    Polyzois, D. [Manitoba Univ., Winnipeg, MB (Canada). Dept. of Civil Engineering

    2008-07-01

    This paper discussed experiments conducted to optimized the advanced composite materials such as fiberglass reinforced plastics (FRP) used to fabricate wind turbine towers. FRP materials are used in tubular steel, lattice, guyed, and reinforced concrete towers. The towers and turbine blades are transported in segments and assembled on-site, sometimes in offshore or remote locations.The FRP composites are used to build towers with a high strength-to-weight ratio as well as to provide resistance to chemical attacks and corrosion. Use of the materials has resulted in towers that do not require heavy installation equipment. Experimental programs were conducted to verify the structural behaviour of the tower structure's individual-scaled cells as well as to evaluate the performance of multi-cell assemblies. Joint assembly designs were optimized, and a filament winding machine was used to conduct the experimental study and to test individual cells. Failure mode analyses were conducted to determine local buckling and shear rupture. Tension, compression, and shear properties of the FRP materials were tested experimentally, and data from the test were then used to develop finite element models of the composite towers as well as to obtain load deflection curves and tip oscillation data. A case study of a 750 kW wind turbine in Churchill, Manitoba was used to test the design. tabs., figs.

  2. Controls of Hydraulic Wind Turbine

    Directory of Open Access Journals (Sweden)

    Zhang Yin

    2016-01-01

    Full Text Available In this paper a hydraulic wind turbine generator system was proposed based on analysis the current wind turbines technologies. The construction and principles were introduced. The mathematical model was verified using MATLAB and AMsim. A displacement closed loop of swash plate of motor and a speed closed loop of generator were setup, a PID control is introduced to maintain a constant speed and fixed frequency at wind turbine generator. Simulation and experiment demonstrated that the system can connect grid to generate electric and enhance reliability. The control system demonstrates a high performance speed regulation and effectiveness. The results are great significant to design a new type hydraulic wind turbine system.

  3. Ceramics for Turbine Engine Applications.

    Science.gov (United States)

    1980-03-01

    permet de travailler en compression. 2 - LES TURBINES CONTRAROTATIVES Connues depuis plus de 50 ans dsns lea turbines A vapeur (A grilles radiales) lea...AD-AO87 594 ADVISORY GROUP FOR AEROSPACE RESEARCH AND DEVELOPMENT--ETC F/6 11/2 CERAMICS FOR TURBINE ENGINE APPICATIONS.(U) MAR 8G H M GURTE, J...for Turbine Engine Applications ( X.,, ~LAJ DISTRIBUTION AND AVAILABILITY Ths ai’-t~ ~ru O ACK COVER forp"~ ~So’ 8 6 0 40 NORTH ATLANTIC TREATY

  4. Advanced LP turbine blade design

    International Nuclear Information System (INIS)

    Jansen, M.; Pfeiffer, R.; Termuehlen, H.

    1990-01-01

    In the 1960's and early 1970's, the development of steam turbines for the utility industry was mainly influenced by the demand for increasing unit sizes. Nuclear plants in particular, required the design of LP turbines with large annulus areas for substantial mass and volumetric steam flows. Since then the development of more efficient LP turbines became an ongoing challenge. Extensive R and D work was performed in order to build efficient and reliable LP turbines often exposed to severe corrosion, erosion and dynamic excitation conditions. This task led to the introduction of an advanced disk-type rotor design for 1800 rpm LP turbines and the application of a more efficient, reaction-type blading for all steam turbine sections including the first stages of LP turbines. The most recent developments have resulted in an advanced design of large LP turbine blading, typically used in the last three stages of each LP turbine flow section. Development of such blading required detailed knowledge of the three dimensional, largely transonic, flow conditions of saturated steam. Also the precise assessment of blade stressing from dynamic conditions, such as speed and torsional resonance, as well as stochastic and aerodynamic excitation is of extreme importance

  5. Biomass combustion gas turbine CHP

    Energy Technology Data Exchange (ETDEWEB)

    Pritchard, D.

    2002-07-01

    This report summarises the results of a project to develop a small scale biomass combustor generating system using a biomass combustor and a micro-gas turbine indirectly fired via a high temperature heat exchanger. Details are given of the specification of commercially available micro-turbines, the manufacture of a biomass converter, the development of a mathematical model to predict the compatibility of the combustor and the heat exchanger with various compressors and turbines, and the utilisation of waste heat for the turbine exhaust.

  6. Wind Turbine Radar Cross Section

    Directory of Open Access Journals (Sweden)

    David Jenn

    2012-01-01

    Full Text Available The radar cross section (RCS of a wind turbine is a figure of merit for assessing its effect on the performance of electronic systems. In this paper, the fundamental equations for estimating the wind turbine clutter signal in radar and communication systems are presented. Methods of RCS prediction are summarized, citing their advantages and disadvantages. Bistatic and monostatic RCS patterns for two wind turbine configurations, a horizontal axis three-blade design and a vertical axis helical design, are shown. The unique electromagnetic scattering features, the effect of materials, and methods of mitigating wind turbine clutter are also discussed.

  7. Small Wind Turbine Technology Assessment

    International Nuclear Information System (INIS)

    Avia Aranda, F.; Cruz Cruz, I.

    1999-01-01

    The result of the study carried out under the scope of the ATYCA project Test Plant of Wind Systems for Isolated Applications, about the state of art of the small wind turbine technology (wind turbines with swept area smaller than 40 m 2 ) is presented. The study analyzes the collected information on 60 models of wind turbines from 23 manufacturers in the worldwide market. Data from Chinese manufacturers, that have a large participation in the total number of small wind turbines in operation, are not included, due to the unavailability of the technical information. (Author) 15 refs

  8. Small Wind Turbine Installation Compatibility Demonstration Methodology

    Science.gov (United States)

    2013-08-01

    wind turbine (HAWT) and one 2.9-kW vertical-axis wind turbine (VAWT), we planned to measure radar, acoustic and seismic, turbulence, bird and...non-issue for small turbines . The majority of studies of bat and bird interactions with wind turbines are for large turbines (BPA 2002; Whittam...et al. 2010). The majority of studies of bat and bird interactions with wind energy facil- ities are for utility-scale turbines (> 1 MW) with

  9. Turbine and Structural Seals Team Facilities

    Data.gov (United States)

    Federal Laboratory Consortium — Seals Team Facilities conceive, develop, and test advanced turbine seal concepts to increase efficiency and durability of turbine engines. Current projects include...

  10. Variable-Speed Power-Turbine Research at Glenn Research Center

    Science.gov (United States)

    Welch, Gerard E.; McVetta, Ashlie B.; Stevens, Mark A.; Howard, Samuel A.; Giel, Paul W.; Ameri, Ali, A.; To, Waiming; Skoch, Gary J.; Thurman, Douglas R.

    2012-01-01

    The main rotors of the NASA Large Civil Tilt-Rotor (LCTR) notional vehicle operate over a wide speed-range, from 100 percent at takeoff to 54 percent at cruise. The variable-speed power turbine (VSPT) offers one approach by which to effect this speed variation. VSPT aerodynamics challenges include high work factors at cruise, wide (40 to 60 ) incidence-angle variations in blade and vane rows over the speed range, and operation at low Reynolds numbers. Rotordynamics challenges include potential responsiveness to shaft modes within the 50 percent VSPT speed-range. A research effort underway at NASA Glenn Research Center, intended to address these key aerodynamic and rotordynamic challenges, is described. Conceptual design and 3-D multistage RANS and URANS analyses, conducted internally and under contract, provide expected VSPT sizing, stage-count, performance and operability information, and maps for system studies. Initial steps toward experimental testing of incidence-tolerant blading in a transonic linear cascade are described, and progress toward development/improvement of a simulation capability for multistage turbines with low Reynolds number transitional flow is summarized. Preliminary rotordynamics analyses indicate that viable concept engines with 50 percent VSPT shaft-speed range. Assessments of potential paths toward VSPT component-level testing are summarized.

  11. Numerical Investigation of the Interaction between Mainstream and Tip Shroud Leakage Flow in a 2-Stage Low Pressure Turbine

    Science.gov (United States)

    Jia, Wei; Liu, Huoxing

    2014-06-01

    The pressing demand for future advanced gas turbine requires to identify the losses in a turbine and to understand the physical mechanisms producing them. In low pressure turbines with shrouded blades, a large portion of these losses is generated by tip shroud leakage flow and associated interaction. For this reason, shroud leakage losses are generally grouped into the losses of leakage flow itself and the losses caused by the interaction between leakage flow and mainstream. In order to evaluate the influence of shroud leakage flow and related losses on turbine performance, computational investigations for a 2-stage low pressure turbine is presented and discussed in this paper. Three dimensional steady multistage calculations using mixing plane approach were performed including detailed tip shroud geometry. Results showed that turbines with shrouded blades have an obvious advantage over unshrouded ones in terms of aerodynamic performance. A loss mechanism breakdown analysis demonstrated that the leakage loss is the main contributor in the first stage while mixing loss dominates in the second stage. Due to the blade-to-blade pressure gradient, both inlet and exit cavity present non-uniform leakage injection and extraction. The flow in the exit cavity is filled with cavity vortex, leakage jet attached to the cavity wall and recirculation zone induced by main flow ingestion. Furthermore, radial gap and exit cavity size of tip shroud have a major effect on the yaw angle near the tip region in the main flow. Therefore, a full calculation of shroud leakage flow is necessary in turbine performance analysis and the shroud geometric features need to be considered during turbine design process.

  12. Phase-I monitoring of standard deviations in multistage linear profiles

    Science.gov (United States)

    Kalaei, Mahdiyeh; Soleimani, Paria; Niaki, Seyed Taghi Akhavan; Atashgar, Karim

    2018-03-01

    In most modern manufacturing systems, products are often the output of some multistage processes. In these processes, the stages are dependent on each other, where the output quality of each stage depends also on the output quality of the previous stages. This property is called the cascade property. Although there are many studies in multistage process monitoring, there are fewer works on profile monitoring in multistage processes, especially on the variability monitoring of a multistage profile in Phase-I for which no research is found in the literature. In this paper, a new methodology is proposed to monitor the standard deviation involved in a simple linear profile designed in Phase I to monitor multistage processes with the cascade property. To this aim, an autoregressive correlation model between the stages is considered first. Then, the effect of the cascade property on the performances of three types of T 2 control charts in Phase I with shifts in standard deviation is investigated. As we show that this effect is significant, a U statistic is next used to remove the cascade effect, based on which the investigated control charts are modified. Simulation studies reveal good performances of the modified control charts.

  13. Experience in North America Tight Oil Reserves Development. Horizontal Wells and Multistage Hydraulic Fracturing

    Directory of Open Access Journals (Sweden)

    R.R. Ibatullin

    2017-09-01

    Full Text Available The accelerated development of horizontal drilling technology in combination with the multistage hydraulic fracturing of the reservoir has expanded the geological conditions for commercial oil production from tight reservoirs in North America. Geological and physical characteristics of tight reservoirs in North America are presented, as well as a comparison of the geological and physical properties of the reservoirs of the Western Canadian Sedimentary Basin and the Volga-Ural oil and gas province, in particular, in the territory of Tatarstan. The similarity of these basins is shown in terms of formation and deposition. New drilling technologies for horizontal wells (HW and multistage hydraulic fracturing are considered. The drilling in tight reservoirs is carried out exclusively on hydrocarbon-based muds The multi-stage fracturing technology with the use of sliding sleeves, and also slick water – a low-viscous carrier for proppant is the most effective solution for conditions similar to tight reservoirs in the Devonian formation of Tatarstan. Tax incentives which are actively used for the development of HW and multistage fracturing technologies in Canada are described. wells, multistage fracturing

  14. Wind Turbine Acoustic Day 2018

    DEFF Research Database (Denmark)

    Mogensen, Jesper; Søndergaard, Bo; Hünerbein, Sabine Von

    The bi-annual event entitled Wind Turbine Acoustic Day dealing with wind turbine noise issues organized by DTU Wind Energy took place on May, 17th 2018 as its third edition. The abstracts and slides for the presentations are reported....

  15. Gas fired advanced turbine system

    Science.gov (United States)

    Lecren, R. T.; White, D. J.

    The basic concept thus derived from the Ericsson cycle is an intercooled, recuperated, and reheated gas turbine. Theoretical performance analyses, however, showed that reheat at high turbine rotor inlet temperatures (TRIT) did not provide significant efficiency gains and that the 50 percent efficiency goal could be met without reheat. Based upon these findings, the engine concept adopted as a starting point for the gas-fired advanced turbine system is an intercooled, recuperated (ICR) gas turbine. It was found that, at inlet temperatures greater than 2450 F, the thermal efficiency could be maintained above 50%, provided that the turbine cooling flows could be reduced to 7% of the main air flow or lower. This dual and conflicting requirement of increased temperatures and reduced cooling will probably force the abandonment of traditional air cooled turbine parts. Thus, the use of either ceramic materials or non-air cooling fluids has to be considered for the turbine nozzle guide vanes and turbine blades. The use of ceramic components for the proposed engine system is generally preferred because of the potential growth to higher temperatures that is available with such materials.

  16. Technical diagnostics of steam turbines

    International Nuclear Information System (INIS)

    Vlckova, B.; Drahy, J.

    1987-01-01

    This paper deals with practical experience in application of technical diagnostics methods to steam turbines, in particular using pedestal and shaft vibration measurements as well as estimation of bearing metal temperature and ultrasound emission signals. An estimation of effectiveness of the diagnostics methods used is given on the basis of experimental investigations made on a 30-MW turbine. (author)

  17. Reliability of wind turbine subassemblies

    NARCIS (Netherlands)

    Spinato, F.; Tavner, P.J.; Bussel, van G.J.W.; Koutoulakos, E.

    2009-01-01

    We have investigated the reliability of more than 6000 modern onshore wind turbines and their subassemblies in Denmark and Germany over 11 years and particularly changes in reliability of generators, gearboxes and converters in a subset of 650 turbines in Schleswig Holstein, Germany. We first start

  18. Wind turbine supply in Canada

    International Nuclear Information System (INIS)

    Snodin, H.

    2007-01-01

    This study reported on wind turbine supplies to the Canadian market. The report was written to address concerns for Canada's supply outlook in the near future due to the booming wind energy market. Turbine shortages have arisen as a result of continued growth in both European and North American markets. Long lead-times on turbine orders are now increasing the pressure to lock in turbine supply during the initial phases of the development process. Future growth of the wind energy industry will be impacted if turbine supply difficulties continue to contribute to uncertainties in the development process. The report provided an overview of the North American and global wind energy markets, as well as a summary of telephone interviews conducted with turbine suppliers. The implications for the future of turbine supply to the Canadian market were also analyzed. It was concluded that policy-makers should focus on supporting the expansion of manufacturing facilities for small wind turbines and control infrastructure in Canada 7 refs., 3 figs

  19. Review: TASHI'S TURBINE

    Directory of Open Access Journals (Sweden)

    Alexander R O'Neill

    2018-05-01

    Full Text Available Amitabh Raj Joshi (director, producer. 2015. Tashi's Turbine. New York City, NY: Vacant Light LLC. 56 mins. http://bit.ly/2tg9fTx, Nepali and Lowa, English subtitles. Color. (Institutional use 320USD; (personal use 34.95USD. In the windswept valleys of Upper Mustang, Nepal, renewable energy is transforming lives. Micro-turbine projects have connected off-grid communities with basic electricity, providing hope for sustainable growth on the Roof of the World. The documentary Tashi's Turbine follows two friends as they experiment with these technologies in Nyamdok Village, along the Sino-Nepali border. Recognizing that high-mountain valleys, including Mustang, Palpa, and Khumbu, are rich in wind resources, Tashi and his friend, Jeevan Kumar Oli, attempt to mitigate poverty using grassroots energy. Tashi Bista was inspired in his youth by tales of "wind machines" at Kagbeni Village in Upper Mustang. In 1987, the Danish Government had funded a twenty-kilowatt turbine in the area; but, it was rapidly decommissioned due to maintenance complications. In 1996, the Government of Nepal established the Alternative Energy Promotion Center (AEPC to revive this and other wind programs and address related challenges. Nevertheless, AEPC's latest Wind Energy Resource Assessment revealed two decades of inaction. Wind programs in other parts of the country remain nascent; much of Central and Western Nepal have yet to be connected to the national grid. Director and cinematographer Amitabh Raj Joshi cultivates a nuanced vision of these developments by juxtaposing majestic landscapes against simple homes and everyday struggles for existence. The film opens with panoramas of the sapphire skies and canvas valleys of Mustang. Minutes later, kerosene fixtures illuminate paltry yields from subsistence harvests; children attempt to study under candlelight, often to no avail. Voicing the narratives of villagers like Chhimi Lhamo, Karma Lutok, and Pemba Tashi, Joshi captures

  20. NEXT GENERATION TURBINE PROGRAM

    Energy Technology Data Exchange (ETDEWEB)

    William H. Day

    2002-05-03

    The Next Generation Turbine (NGT) Program's technological development focused on a study of the feasibility of turbine systems greater than 30 MW that offer improvement over the 1999 state-of-the-art systems. This program targeted goals of 50 percent turndown ratios, 15 percent reduction in generation cost/kW hour, improved service life, reduced emissions, 400 starts/year with 10 minutes to full load, and multiple fuel usage. Improvement in reliability, availability, and maintainability (RAM), while reducing operations, maintenance, and capital costs by 15 percent, was pursued. This program builds on the extensive low emissions stationary gas turbine work being carried out by Pratt & Whitney (P&W) for P&W Power Systems (PWPS), which is a company under the auspices of the United Technologies Corporation (UTC). This study was part of the overall Department of Energy (DOE) NGT Program that extends out to the year 2008. A follow-on plan for further full-scale component hardware testing is conceptualized for years 2002 through 2008 to insure a smooth and efficient transition to the marketplace for advanced turbine design and cycle technology. This program teamed the National Energy Technology Laboratory (NETL), P&W, United Technologies Research Center (UTRC), kraftWork Systems Inc., a subcontractor on-site at UTRC, and Multiphase Power and Processing Technologies (MPPT), an off-site subcontractor. Under the auspices of the NGT Program, a series of analyses were performed to identify the NGT engine system's ability to serve multiple uses. The majority were in conjunction with a coal-fired plant, or used coal as the system fuel. Identified also was the ability of the NGT system to serve as the basis of an advanced performance cycle: the humid air turbine (HAT) cycle. The HAT cycle is also used with coal gasification in an integrated cycle HAT (IGHAT). The NGT systems identified were: (1) Feedwater heating retrofit to an existing coal-fired steam plant, which

  1. Experimental Results of the First Two Stages of an Advanced Transonic Core Compressor Under Isolated and Multi-Stage Conditions

    Science.gov (United States)

    Prahst, Patricia S.; Kulkarni, Sameer; Sohn, Ki H.

    2015-01-01

    NASA's Environmentally Responsible Aviation (ERA) Program calls for investigation of the technology barriers associated with improved fuel efficiency of large gas turbine engines. Under ERA the task for a High Pressure Ratio Core Technology program calls for a higher overall pressure ratio of 60 to 70. This mean that the HPC would have to almost double in pressure ratio and keep its high level of efficiency. The challenge is how to match the corrected mass flow rate of the front two supersonic high reaction and high corrected tip speed stages with a total pressure ratio of 3.5. NASA and GE teamed to address this challenge by using the initial geometry of an advanced GE compressor design to meet the requirements of the first 2 stages of the very high pressure ratio core compressor. The rig was configured to run as a 2 stage machine, with Strut and IGV, Rotor 1 and Stator 1 run as independent tests which were then followed by adding the second stage. The goal is to fully understand the stage performances under isolated and multi-stage conditions and fully understand any differences and provide a detailed aerodynamic data set for CFD validation. Full use was made of steady and unsteady measurement methods to isolate fluid dynamics loss source mechanisms due to interaction and endwalls. The paper will present the description of the compressor test article, its predicted performance and operability, and the experimental results for both the single stage and two stage configurations. We focus the detailed measurements on 97 and 100 of design speed at 3 vane setting angles.

  2. Advanced Hydrogen Turbine Development

    Energy Technology Data Exchange (ETDEWEB)

    Joesph Fadok

    2008-01-01

    Siemens has developed a roadmap to achieve the DOE goals for efficiency, cost reduction, and emissions through innovative approaches and novel technologies which build upon worldwide IGCC operational experience, platform technology, and extensive experience in G-class operating conditions. In Phase 1, the technologies and concepts necessary to achieve the program goals were identified for the gas turbine components and supporting technology areas and testing plans were developed to mitigate identified risks. Multiple studies were conducted to evaluate the impact in plant performance of different gas turbine and plant technologies. 2015 gas turbine technologies showed a significant improvement in IGCC plant efficiency, however, a severe performance penalty was calculated for high carbon capture cases. Thermodynamic calculations showed that the DOE 2010 and 2015 efficiency targets can be met with a two step approach. A risk management process was instituted in Phase 1 to identify risk and develop mitigation plans. For the risks identified, testing and development programs are in place and the risks will be revisited periodically to determine if changes to the plan are necessary. A compressor performance prediction has shown that the design of the compressor for the engine can be achieved with additional stages added to the rear of the compressor. Tip clearance effects were studied as well as a range of flow and pressure ratios to evaluate the impacts to both performance and stability. Considerable data was obtained on the four candidate combustion systems: diffusion, catalytic, premix, and distributed combustion. Based on the results of Phase 1, the premixed combustion system and the distributed combustion system were chosen as having the most potential and will be the focus of Phase 2 of the program. Significant progress was also made in obtaining combustion kinetics data for high hydrogen fuels. The Phase 1 turbine studies indicate initial feasibility of the

  3. Aeroservoelasticity of wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Skovmose Kallesoee, B.

    2007-12-14

    This thesis deals with the fundamental aeroelastic interaction between structural motion, Pitch action and control for a wind turbine blade. As wind turbines become larger, the interaction between pitch action, blade motion, aerodynamic forces, and control become even more important to understand and address. The main contribution of this thesis is the development of an aeroelastic blade model which on the one hand includes the important effects of steady state blade deformation, gravity and pitch action, and on the other it is transparent, suitable for analytical analysis and parameter studies, and furthermore linear and therefore suitable for control design. The development of the primary aeroelastic blade model is divided into four steps: 1) Nonlinear partial differential equations (PDEs) of structural blade motion are derived together with equations of pitch action and rotor speed; the individual terms in these equations are discussed and given physical interpretations; 2) Steady state blade deformation and induced velocities are computed by combining the PDEs with a steady state aerodynamic model; 3) Aeroelastic modes of motion are computed by combining the linearized PDEs with a linear unsteady aerodynamic model; this model is used to analyze how blade deformation effects the modes of motion; and 4) the linear aeroelastic blade model is derived by a modal expansion of the linearized PDEs combined with a linear unsteady aerodynamic model. The aeroelastic blade model has many similarities to a 2D blade section model, and it can be used instead of this in many applications, giving a transparent connection to a real wind turbine blade. In this work the aeroelastic blade model is used to analyze interaction between pitch action, blade motion and wind speed variations. Furthermore the model is used to develop a state estimator for estimating the wind speed and wind shear, and to suggest a load reducing controller. The state estimator estimates the wind shear very

  4. Ceramic Parts for Turbines

    Science.gov (United States)

    Jones, R. D.; Carpenter, Harry W.; Tellier, Jim; Rollins, Clark; Stormo, Jerry

    1987-01-01

    Abilities of ceramics to serve as turbine blades, stator vanes, and other elements in hot-gas flow of rocket engines discussed in report. Ceramics prime candidates, because of resistance to heat, low density, and tolerance of hostile environments. Ceramics considered in report are silicon nitride, silicon carbide, and new generation of such ceramic composites as transformation-toughened zirconia and alumina and particulate- or whisker-reinforced matrices. Report predicts properly designed ceramic components viable in advanced high-temperature rocket engines and recommends future work.

  5. Wind turbine airfoil catalogue

    OpenAIRE

    Bertagnolio, F.; Sørensen, Niels N.; Johansen, Jeppe; Fuglsang, P.

    2001-01-01

    The aim of this work is two-sided. Firstly, experimental results obtained for numerous sets of airfoil measurements (mainly intended for wind turbine applications) are collected and compared with computational results from the 2D Navier-Stokes solverEllipSys2D, as well as results from the panel method code XFOIL. Secondly, we are interested in validating the code EllipSys2D and finding out for which airfoils it does not perform well compared to the experiments, as well as why, when it does so...

  6. Reliability assessment of Wind turbines

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard

    2015-01-01

    Wind turbines can be considered as structures that are in between civil engineering structures and machines since they consist of structural components and many electrical and machine components together with a control system. Further, a wind turbine is not a one-of-a-kind structure...... but manufactured in series production based on many component tests, some prototype tests and zeroseries wind turbines. These characteristics influence the reliability assessment where focus in this paper is on the structural components. Levelized Cost Of Energy is very important for wind energy, especially when...... comparing to other energy sources. Therefore much focus is on cost reductions and improved reliability both for offshore and onshore wind turbines. The wind turbine components should be designed to have sufficient reliability level with respect to both extreme and fatigue loads but also not be too costly...

  7. Megawatt wind turbines gaining momentum

    International Nuclear Information System (INIS)

    Oehlenschlaeger, K.; Madsen, B.T.

    1996-01-01

    Through the short history of the modern wind turbine, electric utilities have made it amply clear that they have held a preference for large scale wind turbines over smaller ones, which is why wind turbine builders through the years have made numerous attempts develop such machines - machines that would meet the technical, aesthetic and economic demands that a customer would require. Considerable effort was put into developing such wind turbines in the early 1980s. There was the U.S. Department of Energy's MOD 1-5 program, which ranged up to 3.2 MW, Denmark's Nibe A and B, 630 kW turbine and the 2 MW Tjaereborg machine, Sweden's Naesudden, 3 MW, and Germany's Growian, 3 MW. Most of these were dismal failures, though some did show the potential of MW technology. (au)

  8. Calculation of gas turbine characteristic

    Science.gov (United States)

    Mamaev, B. I.; Murashko, V. L.

    2016-04-01

    The reasons and regularities of vapor flow and turbine parameter variation depending on the total pressure drop rate π* and rotor rotation frequency n are studied, as exemplified by a two-stage compressor turbine of a power-generating gas turbine installation. The turbine characteristic is calculated in a wide range of mode parameters using the method in which analytical dependences provide high accuracy for the calculated flow output angle and different types of gas dynamic losses are determined with account of the influence of blade row geometry, blade surface roughness, angles, compressibility, Reynolds number, and flow turbulence. The method provides satisfactory agreement of results of calculation and turbine testing. In the design mode, the operation conditions for the blade rows are favorable, the flow output velocities are close to the optimal ones, the angles of incidence are small, and the flow "choking" modes (with respect to consumption) in the rows are absent. High performance and a nearly axial flow behind the turbine are obtained. Reduction of the rotor rotation frequency and variation of the pressure drop change the flow parameters, the parameters of the stages and the turbine, as well as the form of the characteristic. In particular, for decreased n, nonmonotonic variation of the second stage reactivity with increasing π* is observed. It is demonstrated that the turbine characteristic is mainly determined by the influence of the angles of incidence and the velocity at the output of the rows on the losses and the flow output angle. The account of the growing flow output angle due to the positive angle of incidence for decreased rotation frequencies results in a considerable change of the characteristic: poorer performance, redistribution of the pressure drop at the stages, and change of reactivities, growth of the turbine capacity, and change of the angle and flow velocity behind the turbine.

  9. Experimental Investigation of Inlet Distortion in a Multistage Axial Compressor

    Science.gov (United States)

    Rusu, Razvan

    The primary objective of this research is to present results and methodologies used to study total pressure inlet distortion in a multi-stage axial compressor environment. The study was performed at the Purdue 3-Stage Axial Compressor Facility (P3S) which models the final three stages of a production turbofan engine's high-pressure compressor (HPC). The goal of this study was twofold; first, to design, implement, and validate a circumferentially traversable total pressure inlet distortion generation system, and second, to demonstrate data acquisition methods to characterize the inter-stage total pressure flow fields to study the propagation and attenuation of a one-per-rev total pressure distortion. The datasets acquired for this study are intended to support the development and validation of novel computational tools and flow physics models for turbomachinery flow analysis. Total pressure inlet distortion was generated using a series of low-porosity wire gauze screens placed upstream of the compressor in the inlet duct. The screens are mounted to a rotatable duct section that can be precisely controlled. The P3S compressor features fixed instrumentation stations located at the aerodynamic interface plane (AIP) and downstream and upstream of each vane row. Furthermore, the compressor features individually indexable stator vanes which can be traverse by up to two vane passages. Using a series of coordinated distortion and vane traverses, the total pressure flow field at the AIP and subsequent inter-stage stations was characterized with a high circumferential resolution. The uniformity of the honeycomb carrier was demonstrated by characterizing the flow field at the AIP while no distortion screens where installed. Next, the distortion screen used for this study was selected following three iterations of porosity reduction. The selected screen consisted of a series of layered screens with a 100% radial extent and a 120° circumferential extent. A detailed total

  10. Influence of dispatching rules on average production lead time for multi-stage production systems.

    Science.gov (United States)

    Hübl, Alexander; Jodlbauer, Herbert; Altendorfer, Klaus

    2013-08-01

    In this paper the influence of different dispatching rules on the average production lead time is investigated. Two theorems based on covariance between processing time and production lead time are formulated and proved theoretically. Theorem 1 links the average production lead time to the "processing time weighted production lead time" for the multi-stage production systems analytically. The influence of different dispatching rules on average lead time, which is well known from simulation and empirical studies, can be proved theoretically in Theorem 2 for a single stage production system. A simulation study is conducted to gain more insight into the influence of dispatching rules on average production lead time in a multi-stage production system. We find that the "processing time weighted average production lead time" for a multi-stage production system is not invariant of the applied dispatching rule and can be used as a dispatching rule independent indicator for single-stage production systems.

  11. Strategies and limits in multi-stage single-point incremental forming

    DEFF Research Database (Denmark)

    Skjødt, Martin; Silva, M.B.; Martins, P. A. F.

    2010-01-01

    paths. The results also reveal that the sequence of multi-stage forming has a large effect on the location of strain points in the principal strain space. Strain paths are linear in the first stage and highly non-linear in the subsequent forming stages. The overall results show that the experimentally......Multi-stage single-point incremental forming (SPIF) is a state-of-the-art manufacturing process that allows small-quantity production of complex sheet metal parts with vertical walls. This paper is focused on the application of multi-stage SPIF with the objective of producing cylindrical cups......-limit curves and fracture forming-limit curves (FFLCs), numerical simulation, and experimentation, namely the evaluation of strain paths and fracture strains in actual multi-stage parts. Assessment of numerical simulation with experimentation shows good agreement between computed and measured strain and strain...

  12. Preliminary study on functional performance of compound type multistage safety injection tank

    International Nuclear Information System (INIS)

    Bae, Youngmin; Kim, Young In; Kim, Keung Koo

    2015-01-01

    Highlights: • Functional performance of compound type multistage safety injection tanks is studied. • Effects of key design parameters are scrutinized. • Distinctive flow features in compound type safety injection tanks are explored. - Abstract: A parametric study is carried out to evaluate the functional performance of a compound type multistage safety injection tank that would be considered one of the components for the passive safety injection systems in nuclear power plants. The effects of key design parameters such as the initial volume fraction and charging pressure of gas, tank elevation, vertical location of a sparger, resistance coefficient, and operating condition on the injection flow rate are scrutinized along with a discussion of the relevant flow features. The obtained results indicate that the compound type multistage safety injection tank can effectively control the injection flow rate in a passive manner, by switching the driving force for the safety injection from gas pressure to gravity during the refill and reflood phases, respectively

  13. Design of intermediate die shape of multistage profile drawing for linear motion guide

    International Nuclear Information System (INIS)

    Lee, Sang Kon; Lee, Jae Eun; Kim, Sung Min; Kim, Byung Min

    2010-01-01

    The design of an intermediate die shape is very important in multistage profile drawing. In this study, two design methods for the intermediate die shape of a multistage profile drawing for producing a linear motion guide (LM) guide is proposed. One is the electric field analysis method using the equipotential lines generated by electric field analysis, and the other is the virtual die method using a virtual drawing die constructed from the initial material and the final product shape. In order to design the intermediate die shapes of a multistage profile drawing for producing LM guide, the proposed design methods are applied, and then FE analysis and profile drawing experiment are performed. As a result, based on the measurement of dimensional accuracy, it can be known that the intermediate die shape can be designed effectively

  14. Cogeneration steam turbines from Siemens: New solutions

    Science.gov (United States)

    Kasilov, V. F.; Kholodkov, S. V.

    2017-03-01

    The Enhanced Platform system intended for the design and manufacture of Siemens AG turbines is presented. It combines organizational and production measures allowing the production of various types of steam-turbine units with a power of up to 250 MWel from standard components. The Enhanced Platform designs feature higher efficiency, improved reliability, better flexibility, longer overhaul intervals, and lower production costs. The design features of SST-700 and SST-900 steam turbines are outlined. The SST-700 turbine is used in backpressure steam-turbine units (STU) or as a high-pressure cylinder in a two-cylinder condensing turbine with steam reheat. The design of an SST-700 single-cylinder turbine with a casing without horizontal split featuring better flexibility of the turbine unit is presented. An SST-900 turbine can be used as a combined IP and LP cylinder (IPLPC) in steam-turbine or combined-cycle power units with steam reheat. The arrangements of a turbine unit based on a combination of SST-700 and SST-900 turbines or SST-500 and SST-800 turbines are presented. Examples of this combination include, respectively, PGU-410 combinedcycle units (CCU) with a condensing turbine and PGU-420 CCUs with a cogeneration turbine. The main equipment items of a PGU-410 CCU comprise an SGT5-4000F gas-turbine unit (GTU) and STU consisting of SST-700 and SST-900RH steam turbines. The steam-turbine section of a PGU-420 cogeneration power unit has a single-shaft turbine unit with two SST-800 turbines and one SST-500 turbine giving a power output of N el. STU = 150 MW under condensing conditions.

  15. Wind turbine aerodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, D.A. [Waterloo Univ., ON (Canada). Dept. of Mechanical Engineering, Wind Energy Group

    2010-07-01

    The need for clean, renewable electricity in remote communities of Canada and the world was discussed in this presentation. The University of Waterloo Wind Energy Laboratory (WEL) performs research in a large scale indoor environment on wind turbines, blade aerodynamics, and aeroacoustics. A key area of research involves developing turbines for remote off-grid communities where climatic conditions are challenging. This presentation outlined research that is underway on wind energy and off-grid renewable energy systems. Many communities in Canada and remote communities in the rest of the world are not connected to the grid and are dependent on other means to supply electrical energy to their community. Remote communities in northern Canada have no road access and diesel is the dominant source of electrical energy for these communities. All of the community supply of diesel comes from brief winter road access or by air. The presentation discussed existing diesel systems and the solution of developing local renewable energy sources such as wind, hydro, biomass, geothermal, and solar power. Research goals, wind energy activities, experimental equipment, and the results were also presented. Research projects have been developed in wind energy; hydrogen generation/storage/utilization; power electronics/microgrid; and community engagement. figs.

  16. Wind turbine power stations

    International Nuclear Information System (INIS)

    Anon.

    1992-11-01

    The Countryside Council for Wales (CCW's) policy on wind turbine power stations needs to be read in the context of CCW's document Energy:Policy and perspectives for the Welsh countryside. This identifies four levels of action aimed at reducing emission of gases which contribute towards the risk of global warming and gases which cause acid deposition. These are: the need for investment in energy efficiency; the need for investment in conventional power generation in order to meet the highest environmental standards; the need for investment in renewable energy; and the need to use land use transportation policies and decisions to ensure energy efficiency and energy conservation. CCW views wind turbine power stations, along with other renewable energy systems, within this framework. CCW's policy is to welcome the exploitation of renewable energy sources as an element in a complete and environmentally sensitive energy policy, subject to the Environmental Assessment of individual schemes and monitoring of the long-term impact of the various technologies involved. (Author)

  17. Aerodynamics of wind turbines emerging topics

    CERN Document Server

    Amano, R S

    2014-01-01

    Focusing on Aerodynamics of Wind Turbines with topics ranging from Fundamental to Application of horizontal axis wind turbines, this book presents advanced topics including: Basic Theory for Wind turbine Blade Aerodynamics, Computational Methods, and Special Structural Reinforcement Technique for Wind Turbine Blades.

  18. Aircraft propulsion and gas turbine engines

    National Research Council Canada - National Science Library

    El-Sayed, Ahmed F

    2008-01-01

    ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xvii xxxi xxxiii xxxv Part I Aero Engines and Gas Turbines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C...

  19. Configuration of management accounting information system for multi-stage manufacturing

    Science.gov (United States)

    Mkrtychev, S. V.; Ochepovsky, A. V.; Enik, O. A.

    2018-05-01

    The article presents an approach to configuration of a management accounting information system (MAIS) that provides automated calculations and the registration of normative production losses in multi-stage manufacturing. The use of MAIS with the proposed configuration at the enterprises of textile and woodworking industries made it possible to increase the accuracy of calculations for normative production losses and to organize accounting thereof with the reference to individual stages of the technological process. Thus, high efficiency of multi-stage manufacturing control is achieved.

  20. Hydrogen enriched gas production in a multi-stage downdraft gasification process

    International Nuclear Information System (INIS)

    Dutta, A.; Jarungthammachote, S.

    2009-01-01

    To achieve hydrogen enriched and low-tar producer gas, multi-stage air-blown and air-steam gasification were studied in this research. Results showed that the tar content from multi-stage air-blown and air-steam gasification was lower compared to the average value of that from downdraft gasification. It was also seen that an air-steam gasification process could potentially increase the hydrogen concentration in the producer gas in the expense of carbon monoxide; however, the summation of hydrogen and carbon monoxide in the producer gas was increased. (author)

  1. The Expected Loss in the Discretization of Multistage Stochastic Programming Problems - Estimation and Convergence Rate

    Czech Academy of Sciences Publication Activity Database

    Šmíd, Martin

    2009-01-01

    Roč. 165, č. 1 (2009), s. 29-45 ISSN 0254-5330 R&D Projects: GA ČR GA402/04/1294 Institutional research plan: CEZ:AV0Z10750506 Keywords : multistage stochastic programming problems * approximation * discretization * Monte Carlo Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 0.961, year: 2009 http://library.utia.cas.cz/separaty/2008/E/smid-the expected loss in the discretization of multistage stochastic programming problems - estimation and convergence rate.pdf

  2. Effectiveness of multi-stage scrubbers in reducing emissions of air pollutants from pig houses

    OpenAIRE

    Zhao, Y.; Aarnink, A.J.A.; Jong, de, M.C.M.; Ogink, N.W.M.; Groot Koerkamp, P.W.G.

    2011-01-01

    Emissions of air pollutants from livestock houses may raise environmental problems and pose hazards to public health. They can be reduced by scrubbers installed at the air outlets of livestock houses. In this study, three multi-stage scrubbers were evaluated in terms of their effectiveness in reducing emissions of airborne dust, total bacteria, ammonia, and CO2 from pig houses in winter. The three multi-stage scrubbers were one double-stage scrubber (acid stage+ bio-filter), one double-stage ...

  3. Potential health impact of wind turbines

    International Nuclear Information System (INIS)

    2010-05-01

    In response to public health concerns about wind turbines, a study was conducted to review the scientific evidence on the potential health effects of wind turbines. Several research questions were examined, including scientific evidence on the potential health impacts of wind turbines; the relationship between wind turbine noise and health; the relationship between low frequency sound, infrasound and health; assessment of exposure to wind turbines; wind turbine health and safety hazards and Ontario wind turbine setbacks; community consultation prior to wind farm construction and data gaps and research needs. The study showed that although some people living near wind turbines reported symptoms such as dizziness, headaches, and sleep disturbance, the scientific evidence available to date does not demonstrate a direct causal link between wind turbine noise and adverse health effects. The sound level from wind turbines at common residential setbacks is not sufficient to cause hearing impairment or other direct health effects, although some people may find it annoying. 41 refs., 1 appendix.

  4. Two stage turbine for rockets

    Science.gov (United States)

    Veres, Joseph P.

    1993-01-01

    The aerodynamic design and rig test evaluation of a small counter-rotating turbine system is described. The advanced turbine airfoils were designed and tested by Pratt & Whitney. The technology represented by this turbine is being developed for a turbopump to be used in an advanced upper stage rocket engine. The advanced engine will use a hydrogen expander cycle and achieve high performance through efficient combustion of hydrogen/oxygen propellants, high combustion pressure, and high area ratio exhaust nozzle expansion. Engine performance goals require that the turbopump drive turbines achieve high efficiency at low gas flow rates. The low mass flow rates and high operating pressures result in very small airfoil heights and diameters. The high efficiency and small size requirements present a challenging turbine design problem. The shrouded axial turbine blades are 50 percent reaction with a maximum thickness to chord ratio near 1. At 6 deg from the tangential direction, the nozzle and blade exit flow angles are well below the traditional design minimum limits. The blade turning angle of 160 deg also exceeds the maximum limits used in traditional turbine designs.

  5. Steam turbines for nuclear power plants

    International Nuclear Information System (INIS)

    Kosyak, Yu.F.

    1978-01-01

    Considered are the peculiarities of the design and operation of steam turbines, condensers and supplementary equipment of steam turbines for nuclear power plants; described are the processes of steam flow in humid-steam turbines, calculation and selection principles of main parameters of heat lines. Designs of the turbines installed at the Charkov turbine plant are described in detail as well as of those developed by leading foreign turbobuilding firms

  6. Aminoglycoside-induced and non-syndromic hearing loss is associated with the G7444A mutation in the mitochondrial COI/tRNASer(UCN) genes in two Chinese families

    International Nuclear Information System (INIS)

    Zhu Yi; Qian Yaping; Tang Xiaowen; Wang Jindan; Yang Li; Liao Zhisu; Li Ronghua; Ji Jinzhang; Li Zhiyuan; Chen Jianfu; Choo, Daniel I.; Lu Jianxin; Guan Minxin

    2006-01-01

    We report here the clinical, genetic, and molecular characterization of two Chinese families with aminoglycoside induced and non-syndromic hearing impairment. Clinical and genetic evaluations revealed the variable severity and age-of-onset in hearing impairment in these families. Strikingly, there were extremely low penetrances of hearing impairment in these Chinese families. Sequence analysis of the complete mitochondrial genomes in these pedigrees showed the distinct sets of mtDNA polymorphism, in addition to the identical G7444A mutation associated with hearing loss. Indeed, the G7444A mutation in the CO1 gene and the precursor of tRNA Ser(UCN) gene is present in homoplasmy only in the maternal lineage of those pedigrees but not other members of these families and 164 Chinese controls. Their mitochondrial genomes belong to the Eastern Asian haplogroups C5a and D4a, respectively. In fact, the occurrence of the G7444A mutation in these several genetically unrelated subjects affected by hearing impairment strongly indicates that this mutation is involved in the pathogenesis of hearing impairment. However, there was the absence of other functionally significant mtDNA mutations in two Chinese pedigrees carrying the G7444A mutation. Therefore, nuclear modifier gene(s) or aminoglycoside(s) may play a role in the phenotypic expression of the deafness-associated G7444A mutation in these Chinese pedigrees

  7. Optimization of hydraulic turbine diffuser

    Directory of Open Access Journals (Sweden)

    Moravec Prokop

    2016-01-01

    Full Text Available Hydraulic turbine diffuser recovers pressure energy from residual kinetic energy on turbine runner outlet. Efficiency of this process is especially important for high specific speed turbines, where almost 50% of available head is utilized within diffuser. Magnitude of the coefficient of pressure recovery can be significantly influenced by designing its proper shape. Present paper focuses on mathematical shape optimization method coupled with CFD. First method is based on direct search Nelder-Mead algorithm, while the second method employs adjoint solver and morphing. Results obtained with both methods are discussed and their advantages/disadvantages summarized.

  8. Active control: Wind turbine model

    DEFF Research Database (Denmark)

    Bindner, H.

    1999-01-01

    This report is a part of the reporting of the work done in the project 'Active Control of Wind Turbines'. This project aim is to develop a simulation model for design of control systems for turbines with pitch control and to use that model to designcontrollers. This report describes the model...... validation as well as parameter estimation. The model includes a simple model of the structure of the turbine including tower and flapwise blade bending,a detailed model of the gear box and induction generator, a linearized aerodynamic model including modelling of induction lag and actuator and sensor models...

  9. Steam turbines for PWR stations

    International Nuclear Information System (INIS)

    Muscroft, J.

    1989-01-01

    The thermodynamic cycle requirements and mechanical design features applying to modern GEC 3000 rev/min steam turbines for pressurised water reactor power stations are reviewed. The most recent developments include machines of 630 MW and 985 MW output which are currently under construction. The importance of service experience with nuclear wet steam turbines associated with a variety of types of water cooled reactor and its relevance to the design of modern 3000 rev/min turbines for pressurised water reactor applications is emphasised. (author)

  10. Simplified Multi-Stage and Per Capita Convergence: an analysis of two climate regimes for differentiation of commitments

    NARCIS (Netherlands)

    Elzen MGJ den; Berk MM; Lucas P; KMD

    2004-01-01

    This report describes and analyses in detail two climate regimes for differentiating commitments: the simplified Multi-Stage and Per Capita Convergence approaches. The Multi-Stage approach consists of a system to divide countries into groups with different types of commitments (stages). The Per

  11. Superconducting Wind Turbine Generators

    DEFF Research Database (Denmark)

    Mijatovic, Nenad

    A HTS machine could be a way to address some of the technical barriers offshore wind energy is about to face. Due to the superior power density of HTS machines, this technology could become a milestone on which many, including the wind industry, will rely in the future. The work presented...... in this thesis is a part of a larger endeavor, the Superwind project that focused on identifying the potentials that HTS machines could offer to the wind industry and addressing some of the challenges in the process. In order to identify these challenges, I have design and constructed a HTS machine experimental...... setup which is made to serve as precursor, leading towards an optimized HTS machine concept proposed for wind turbines. In part, the work presented in this thesis will focus on the description of the experimental setup and reasoning behind the choices made during the design. The setup comprises from...

  12. Sprayed skin turbine component

    Science.gov (United States)

    Allen, David B

    2013-06-04

    Fabricating a turbine component (50) by casting a core structure (30), forming an array of pits (24) in an outer surface (32) of the core structure, depositing a transient liquid phase (TLP) material (40) on the outer surface of the core structure, the TLP containing a melting-point depressant, depositing a skin (42) on the outer surface of the core structure over the TLP material, and heating the assembly, thus forming both a diffusion bond and a mechanical interlock between the skin and the core structure. The heating diffuses the melting-point depressant away from the interface. Subsurface cooling channels (35) may be formed by forming grooves (34) in the outer surface of the core structure, filling the grooves with a fugitive filler (36), depositing and bonding the skin (42), then removing the fugitive material.

  13. Multiple Turbine Wakes

    DEFF Research Database (Denmark)

    Machefaux, Ewan; Mann, Jakob

    and to obtain an estimate of the wake expansion in a fixed frame of reference. A comparison of selected datasets from the campaign showed good far wake agreements of mean wake expansion with Actuator Line CFD computations and simpler engineering models. An empirical relationship, relating maximum wake induction...... for modeling the resulting double wake deficit is only relevant at high turbine thrust coefficients. For high wind speed and low thrust coefficient, linear summation should be primarily used. The first iteration of a new engineering model capable of modeling the overlapped wake deficit is formulated and its...... measurement and simulation is seen in both the fixed and the meandering frame of reference. A benchmark of several wake accumulation models is performed as a basis for the subsequent development of an engineering model for wake interaction.Finally, the validated numerical CFD model is used as part...

  14. Aircraft gas turbines

    Energy Technology Data Exchange (ETDEWEB)

    Arai, M [Kawasaki Heavy Industries Ltd., Kobe (Japan)

    1995-03-01

    Recently the international relationship has been playing an important role in the research, development and production of the aircraft gas turbine. The YSX, which is supposed to be the 100-seat class commercial aircraft, has been planned by Japan Aircraft Development (JADC) as an international cooperative project. Recently many western aeroengine companies have offered the collaboration of small turbofan engines which would be installed on YSX to Japanese aeroengine companies (IHI, KHI and MHI). The YSX is powered by 16,000-20,000 1bs thrust class engines. As for medium turbofan engine (V2500), the V 2500 family of 22,000 to 30,000 1bs thrust has been developed since 1983 through international collaboration by seven aeroengine companies in five nations. In this paper, the recent Japan`s activities of the research, development and production with viewing the world-wide movement, are described. 6 figs.

  15. Wind turbine airfoil catalogue

    DEFF Research Database (Denmark)

    Bertagnolio, F.; Sørensen, Niels N.; Johansen, Jeppe

    2001-01-01

    The aim of this work is two-sided. Firstly, experimental results obtained for numerous sets of airfoil measurements (mainly intended for wind turbine applications) are collected and compared with computational results from the 2D Navier-Stokes solverEllipSys2D, as well as results from the panel...... method code XFOIL. Secondly, we are interested in validating the code EllipSys2D and finding out for which airfoils it does not perform well compared to the experiments, as well as why, when it does so. Theairfoils are classified according to the agreement between the numerical results and experimental...... data. A study correlating the available data and this classification is performed. It is found that transition modelling is to a large extent responsible forthe poor quality of the computational results for most of the considered airfoils. The transition model mechanism that leads...

  16. Gas Turbine Engine Having Fan Rotor Driven by Turbine Exhaust and with a Bypass

    Science.gov (United States)

    Suciu, Gabriel L. (Inventor); Chandler, Jesse M. (Inventor)

    2016-01-01

    A gas turbine engine has a core engine incorporating a core engine turbine. A fan rotor is driven by a fan rotor turbine. The fan rotor turbine is in the path of gases downstream from the core engine turbine. A bypass door is moveable from a closed position at which the gases from the core engine turbine pass over the fan rotor turbine, and moveable to a bypass position at which the gases are directed away from the fan rotor turbine. An aircraft is also disclosed.

  17. A semi-analytical modelling of multistage bunch compression with collective effects

    International Nuclear Information System (INIS)

    Zagorodnov, Igor; Dohlus, Martin

    2010-07-01

    In this paper we introduce an analytical solution (up to the third order) for a multistage bunch compression and acceleration system without collective effects. The solution for the system with collective effects is found by an iterative procedure based on this analytical result. The developed formalism is applied to the FLASH facility at DESY. Analytical estimations of RF tolerances are given. (orig.)

  18. A semi-analytical modelling of multistage bunch compression with collective effects

    Energy Technology Data Exchange (ETDEWEB)

    Zagorodnov, Igor; Dohlus, Martin

    2010-07-15

    In this paper we introduce an analytical solution (up to the third order) for a multistage bunch compression and acceleration system without collective effects. The solution for the system with collective effects is found by an iterative procedure based on this analytical result. The developed formalism is applied to the FLASH facility at DESY. Analytical estimations of RF tolerances are given. (orig.)

  19. Multi-stage decoding for multi-level block modulation codes

    Science.gov (United States)

    Lin, Shu

    1991-01-01

    In this paper, we investigate various types of multi-stage decoding for multi-level block modulation codes, in which the decoding of a component code at each stage can be either soft-decision or hard-decision, maximum likelihood or bounded-distance. Error performance of codes is analyzed for a memoryless additive channel based on various types of multi-stage decoding, and upper bounds on the probability of an incorrect decoding are derived. Based on our study and computation results, we find that, if component codes of a multi-level modulation code and types of decoding at various stages are chosen properly, high spectral efficiency and large coding gain can be achieved with reduced decoding complexity. In particular, we find that the difference in performance between the suboptimum multi-stage soft-decision maximum likelihood decoding of a modulation code and the single-stage optimum decoding of the overall code is very small: only a fraction of dB loss in SNR at the probability of an incorrect decoding for a block of 10(exp -6). Multi-stage decoding of multi-level modulation codes really offers a way to achieve the best of three worlds, bandwidth efficiency, coding gain, and decoding complexity.

  20. Effectiveness of multi-stage scrubbers in reducing emissions of air pollutants from pig houses

    NARCIS (Netherlands)

    Zhao, Y.; Aarnink, A.J.A.; Jong, de M.C.M.; Ogink, N.W.M.; Groot Koerkamp, P.W.G.

    2011-01-01

    Emissions of air pollutants from livestock houses may raise environmental problems and pose hazards to public health. They can be reduced by scrubbers installed at the air outlets of livestock houses. In this study, three multi-stage scrubbers were evaluated in terms of their effectiveness in

  1. Research on EMI Reduction of Multi-stage Interleaved Bridgeless Power Factor Corrector

    DEFF Research Database (Denmark)

    Li, Qingnan; Thomsen, Ole Cornelius; Andersen, Michael A. E.

    2012-01-01

    Working as an electronic pollution eliminator, the Power Factor Corrector's (PFC) own Electromagnetic Interference (EMI) problems have been blocking its performance improvement for long. In this paper, a systematic research on EMI generation of a multi-stage Two-Boost-Circuit Interleaved Bridgeless...

  2. Setting safety stocks in multi-stage inventory systems under rolling horizon mathematical programming models

    NARCIS (Netherlands)

    Boulaksil, Y.; Fransoo, J.C.; van Halm, E.N.G.

    2009-01-01

    This paper considers the problem of determining safety stocks in multi-item multi-stage inventory systems that face demand uncertainties. Safety stocks are necessary to make the supply chain, which is driven by forecasts of customer orders, responsive to (demand) uncertainties and to achieve

  3. A Multi-Stage Maturity Model for Long-Term IT Outsourcing Relationship Success

    Science.gov (United States)

    Luong, Ming; Stevens, Jeff

    2015-01-01

    The Multi-Stage Maturity Model for Long-Term IT Outsourcing Relationship Success, a theoretical stages-of-growth model, explains long-term success in IT outsourcing relationships. Research showed the IT outsourcing relationship life cycle consists of four distinct, sequential stages: contract, transition, support, and partnership. The model was…

  4. A New Feature Ensemble with a Multistage Classification Scheme for Breast Cancer Diagnosis

    Directory of Open Access Journals (Sweden)

    Idil Isikli Esener

    2017-01-01

    Full Text Available A new and effective feature ensemble with a multistage classification is proposed to be implemented in a computer-aided diagnosis (CAD system for breast cancer diagnosis. A publicly available mammogram image dataset collected during the Image Retrieval in Medical Applications (IRMA project is utilized to verify the suggested feature ensemble and multistage classification. In achieving the CAD system, feature extraction is performed on the mammogram region of interest (ROI images which are preprocessed by applying a histogram equalization followed by a nonlocal means filtering. The proposed feature ensemble is formed by concatenating the local configuration pattern-based, statistical, and frequency domain features. The classification process of these features is implemented in three cases: a one-stage study, a two-stage study, and a three-stage study. Eight well-known classifiers are used in all cases of this multistage classification scheme. Additionally, the results of the classifiers that provide the top three performances are combined via a majority voting technique to improve the recognition accuracy on both two- and three-stage studies. A maximum of 85.47%, 88.79%, and 93.52% classification accuracies are attained by the one-, two-, and three-stage studies, respectively. The proposed multistage classification scheme is more effective than the single-stage classification for breast cancer diagnosis.

  5. Multi-Stage Admission Control for Load Balancing in Next Generation Systems

    DEFF Research Database (Denmark)

    Mihovska, Albena D.; Anggorojati, Bayu; Luo, Jijun

    2008-01-01

    This paper describes a load-dependent multi-stage admission control suitable for next generation systems. The concept uses decision polling in entities located at different levels of the architecture hierarchy and based on the load to activate a sequence of actions related to the admission...

  6. Seven prostate cancer susceptibility loci identified by a multi-stage genome-wide association study

    DEFF Research Database (Denmark)

    Kote-Jarai, Zsofia; Olama, Ali Amin Al; Giles, Graham G

    2011-01-01

    Prostate cancer (PrCa) is the most frequently diagnosed male cancer in developed countries. We conducted a multi-stage genome-wide association study for PrCa and previously reported the results of the first two stages, which identified 16 PrCa susceptibility loci. We report here the results of st...

  7. Influence of perforation erosion on multiple growing hydraulic fractures in multi-stage fracturing

    Directory of Open Access Journals (Sweden)

    Yongming Li

    2018-02-01

    Full Text Available In multi-stage hydraulic fracturing, the limited-entry method is widely used to promote uniform growth of multiple fractures. However, this method's effectiveness may be lost because the perforations will be eroded gradually during the fracturing period. In order to study the influence of perforation erosion on multiple growing hydraulic fractures, we combined the solid–fluid coupled model of hydraulic fracture growth with an empirical model of perforation erosion to implement numerical simulation. The simulations show clearly that the erosion of perforation will significantly deteriorate the non-uniform growth of multiple fractures. Based on the numerical model, we also studied the influences of proppant concentration and injection rates on perforation erosion in multi-stage hydraulic fracturing. The results indicate that the initial erosion rates become higher with the rising proppant concentration, but the growth of multiple hydraulic fractures is not sensitive to the varied proppant concentration. In addition, higher injection rates are beneficial significantly to the limited-entry design, leading to more uniform growth of fractures. Thus, in multi-stage hydraulic fracturing enough high injection rates are proposed to keep uniform growths. Keywords: Unconventional oil and gas reservoir, Horizontal well, Perforation friction, Perforation erosion, Multi-stage hydraulic fracturing, Numerical simulation, Mathematic model, Uniform growth of fractures

  8. Multi-Stage Selective Catalytic Reduction of NOx in Lean-Burn Engine Exhaust

    National Research Council Canada - National Science Library

    Penetrante, B

    1997-01-01

    .... A plasma can also be used to oxidize NO to NO2. This paper compares the multi-stage catalytic scheme with the plasma-assisted catalytic scheme for reduction of NOx in lean-burn engine exhausts. The advantages of plasma oxidation over catalytic oxidation are presented.

  9. Automated simultaneous assembly of multi-stage testing for the uniform CPA examination

    NARCIS (Netherlands)

    Breithaupt, Krista; Ariel, A.; Veldkamp, Bernard P.

    2004-01-01

    Some solutions used in the assembly of the computerized Uniform Certified Public Accountancy (CPA) licensing examination are offered as practical alternatives for operational programs producing large numbers of forms. The Uniform CPA examination will be offered as an adaptive multi-stage test (MST)

  10. The effect of tooling deformation on process control in multistage metal forming

    NARCIS (Netherlands)

    Havinga, Gosse Tjipke; van den Boogaard, Antonius H.; Chinesta, F; Cueto, E; Abisset-Chavanne, E.

    2016-01-01

    Forming of high-strength steels leads to high loads within the production process. In multistage metal forming, the loads in different process stages are transferred to the other stages through elastic deformation of the stamping press. This leads to interactions between process steps, affecting the

  11. The multi-stage proportional chamber in the detection of Cherenkov rings for particle recognition

    International Nuclear Information System (INIS)

    Sauli, F.

    1979-01-01

    The multi-stage proportional chamber enables very high gains of 10 6 or more to be reached in gaseous mixtures offering a very good quantum efficiency in the far ultra-violet range. This makes it an ideal instrument for detecting and locating the photons emitted by Cerenkov effect in appropriate radiators [fr

  12. Multi-stage Optimization of Matchings in Trees with Application to Kidney Exchange

    KAUST Repository

    Mankowski, Michal; Moshkov, Mikhail

    2017-01-01

    In this paper, we propose a method for multi-stage optimization of matchings in trees relative to different weight functions that assign positive weights to the edges of the trees. This method can be useful in transplantology where nodes of the tree

  13. Finite Element Analysis and Optimization for the Multi-stage Deep Drawing of Molybdenum Sheet

    International Nuclear Information System (INIS)

    Kim, Heung-Kyu; Hong, Seok Kwan; Kang, Jeong Jin; Heo, Young-moo; Lee, Jong-Kil; Jeon, Byung-Hee

    2005-01-01

    Molybdenum, a bcc refractory metal with a melting point of about 2600 deg. C, has a high heat and electrical conductivity. In addition, it remains strong mechanically at high temperatures as well as at low temperatures. Therefore it is a technologically very important material for the applications operating at high temperatures. However, a multi-stage process is required due to the low drawability for making a deep drawn part from the molybdenum sheet. In this study, a multi-stage deep drawing process for a molybdenum circular cup was designed by combining the drawing with the ironing, which was effective for the low drawability materials. A parametric study by FE analysis for the multi-stage deep drawing was conducted for evaluation of the design variables effect. Based on the FE analysis result, the multi-stage deep drawing process was parameterized by the design variables, and an optimum process design was obtained by the process optimization based on the FE simulation at each stage

  14. Metabolite Identification Using Automated Comparison of High-Resolution Multistage Mass Spectral Trees

    NARCIS (Netherlands)

    Rojas-Cherto, M.; Peironcely, J.E.; Kasper, P.T.; Hooft, van der J.J.J.; Vos, de R.C.H.; Vreeken, R.; Hankemeier, T.; Reijmers, T.

    2012-01-01

    Multistage mass spectrometry (MSn) generating so-called spectral trees is a powerful tool in the annotation and structural elucidation of metabolites and is increasingly used in the area of accurate mass LC/MS-based metabolomics to identify unknown, but biologically relevant, compounds. As a

  15. Interaction between Gaming and Multistage Guiding Strategies on Students' Field Trip Mobile Learning Performance and Motivation

    Science.gov (United States)

    Chen, Chih-Hung; Liu, Guan-Zhi; Hwang, Gwo-Jen

    2016-01-01

    In this study, an integrated gaming and multistage guiding approach was proposed for conducting in-field mobile learning activities. A mobile learning system was developed based on the proposed approach. To investigate the interaction between the gaming and guiding strategies on students' learning performance and motivation, a 2 × 2 experiment was…

  16. A study of routing algorithms for SCI-Based multistage networks

    International Nuclear Information System (INIS)

    Wu Bin; Kristiansen, E.; Skaali, B.; Bogaerts, A.; )

    1994-03-01

    The report deals with a particular class of multistage Scalable Coherent Interface (SCI) network systems and two important routing algorithms, namely self-routing and table-look up routing. The effect of routing delay on system performance is investigated by simulations. Adaptive routing and deadlock-free routing are studied. 8 refs., 11 figs., 1 tab

  17. Multistage Effort and the Equity Structure of Venture Investment Based on Reciprocity Motivation

    Directory of Open Access Journals (Sweden)

    Chuan Ding

    2015-01-01

    Full Text Available For venture capitals, it is a long process from an entry to its exit. In this paper, the activity of venture investment will be divided into multistages. And, according to the effort level entrepreneurs will choose, the venture capitalists will provide an equity structure at the very beginning. As a benchmark for comparison, we will establish two game models on multistage investment under perfect rationality: a cooperative game model and a noncooperative one. Further, as a cause of pervasive psychological preference behavior, reciprocity motivation will influence the behavior of the decision-makers. Given this situation, Rabin’s reciprocity motivation theory will be applied to the multistage game model of the venture investment, and multistage behavior game model will be established as well, based on the reciprocity motivation. By looking into the theoretical derivations and simulation studies, we find that if venture capitalists and entrepreneurs both have reciprocity preferences, their utility would have been Pareto improvement compared with those under perfect rationality.

  18. Multi-stage volcanic island flank collapses with coeval explosive caldera-forming eruptions.

    Science.gov (United States)

    Hunt, James E; Cassidy, Michael; Talling, Peter J

    2018-01-18

    Volcanic flank collapses and explosive eruptions are among the largest and most destructive processes on Earth. Events at Mount St. Helens in May 1980 demonstrated how a relatively small (300 km 3 ), but can also occur in complex multiple stages. Here, we show that multistage retrogressive landslides on Tenerife triggered explosive caldera-forming eruptions, including the Diego Hernandez, Guajara and Ucanca caldera eruptions. Geochemical analyses were performed on volcanic glasses recovered from marine sedimentary deposits, called turbidites, associated with each individual stage of each multistage landslide. These analyses indicate only the lattermost stages of subaerial flank failure contain materials originating from respective coeval explosive eruption, suggesting that initial more voluminous submarine stages of multi-stage flank collapse induce these aforementioned explosive eruption. Furthermore, there are extended time lags identified between the individual stages of multi-stage collapse, and thus an extended time lag between the initial submarine stages of failure and the onset of subsequent explosive eruption. This time lag succeeding landslide-generated static decompression has implications for the response of magmatic systems to un-roofing and poses a significant implication for ocean island volcanism and civil emergency planning.

  19. High-efficiency wind turbine

    Science.gov (United States)

    Hein, L. A.; Myers, W. N.

    1980-01-01

    Vertical axis wind turbine incorporates several unique features to extract more energy from wind increasing efficiency 20% over conventional propeller driven units. System also features devices that utilize solar energy or chimney effluents during periods of no wind.

  20. Probabilistic Design of Wind Turbines

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Toft, H.S.

    2010-01-01

    Probabilistic design of wind turbines requires definition of the structural elements to be included in the probabilistic basis: e.g., blades, tower, foundation; identification of important failure modes; careful stochastic modeling of the uncertain parameters; recommendations for target reliability....... It is described how uncertainties in wind turbine design related to computational models, statistical data from test specimens, results from a few full-scale tests and from prototype wind turbines can be accounted for using the Maximum Likelihood Method and a Bayesian approach. Assessment of the optimal...... reliability level by cost-benefit optimization is illustrated by an offshore wind turbine example. Uncertainty modeling is illustrated by an example where physical, statistical and model uncertainties are estimated....

  1. Reliability Assessment Of Wind Turbines

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard

    2014-01-01

    Reduction of cost of energy for wind turbines are very important in order to make wind energy competitive compared to other energy sources. Therefore the turbine components should be designed to have sufficient reliability but also not be too costly (and safe). This paper presents models...... for uncertainty modeling and reliability assessment of especially the structural components such as tower, blades, substructure and foundation. But since the function of a wind turbine is highly dependent on many electrical and mechanical components as well as a control system also reliability aspects...... of these components are discussed and it is described how there reliability influences the reliability of the structural components. Two illustrative examples are presented considering uncertainty modeling, reliability assessment and calibration of partial safety factors for structural wind turbine components exposed...

  2. Boiler-turbine life extension

    Energy Technology Data Exchange (ETDEWEB)

    Natzkov, S. [TOTEMA, Ltd., Sofia (Bulgaria); Nikolov, M. [CERB, Sofia (Bulgaria)

    1995-12-01

    The design life of the main power equipment-boilers and turbines is about 105 working hours. The possibilities for life extension are after normatively regulated control tests. The diagnostics and methodology for Boilers and Turbines Elements Remaining Life Assessment using up to date computer programs, destructive and nondestructive control of metal of key elements of units equipment, metal creep and low cycle fatigue calculations. As well as data for most common damages and some technical decisions for elements life extension are presented.

  3. CFD analysis of a Darrieus wind turbine

    Science.gov (United States)

    Niculescu, M. L.; Cojocaru, M. G.; Pricop, M. V.; Pepelea, D.; Dumitrache, A.; Crunteanu, D. E.

    2017-07-01

    The Darrieus wind turbine has some advantages over the horizontal-axis wind turbine. Firstly, its tip speed ratio is lower than that of the horizontal-axis wind turbine and, therefore, its noise is smaller, privileging their placement near populated areas. Secondly, the Darrieus wind turbine does needs no orientation mechanism with respect to wind direction in contrast to the horizontal-axis wind turbine. However, the efficiency of the Darrieus wind turbine is lower than that of the horizontal-axis wind turbine since its aerodynamics is much more complex. With the advances in computational fluids and computers, it is possible to simulate the Darrieus wind turbine more accurately to understand better its aerodynamics. For these reasons, the present papers deals with the computational aerodynamics of a Darrieus wind turbine applying the state of the art of CFD methods (anisotropic turbulence models, transition from laminar to turbulent, scale adaptive simulation) to better understand its unsteady behavior.

  4. Variable Pitch Darrieus Water Turbines

    Science.gov (United States)

    Kirke, Brian; Lazauskas, Leo

    In recent years the Darrieus wind turbine concept has been adapted for use in water, either as a hydrokinetic turbine converting the kinetic energy of a moving fluid in open flow like an underwater wind turbine, or in a low head or ducted arrangement where flow is confined, streamtube expansion is controlled and efficiency is not subject to the Betz limit. Conventional fixed pitch Darrieus turbines suffer from two drawbacks, (i) low starting torque and (ii) shaking due to cyclical variations in blade angle of attack. Ventilation and cavitation can also cause problems in water turbines when blade velocities are high. Shaking can be largely overcome by the use of helical blades, but these do not produce large starting torque. Variable pitch can produce high starting torque and high efficiency, and by suitable choice of pitch regime, shaking can be minimized but not entirely eliminated. Ventilation can be prevented by avoiding operation close to a free surface, and cavitation can be prevented by limiting blade velocities. This paper summarizes recent developments in Darrieus water turbines, some problems and some possible solutions.

  5. Noise immission from wind turbines

    International Nuclear Information System (INIS)

    1999-01-01

    The project has dealt with practical ways to reduce the influence of background noise caused by wind acting on the measuring microphones. The uncertainty of measured noise emission (source strength) has been investigated. The main activity was a Round Robin Test involving measurements by five laboratories at the same wind turbine. Each laboratory brought its own instrumentation and performed the measurements and analyses according to their interpretation. The tonality of wind turbine noise is an essential component of the noise impact on the environment. In the present project the uncertainty in the newest existing methods for assessing tonality was investigated. The project included noise propagation measurements in different weather conditions around wind turbines situated in different types of terrain. The results were used to validate a noise propagation model developed in the project. Finally, the project also included a study with listeners evaluating recordings of wind turbine noise. The results are intended as guidance for wind turbine manufacturers in identifying the aspects of wind turbine noise most important to annoyance. (author)

  6. Active control: Wind turbine model

    Energy Technology Data Exchange (ETDEWEB)

    Bindner, Henrik

    1999-07-01

    This report is a part of the reporting of the work done in the project `Active Control of Wind Turbines`. This project aim is to develop a simulation model for design of control systems for turbines with pitch control and to use that model to design controllers. This report describes the model developed for controller design and analysis. Emphasis has been put on establishment of simple models describing the dynamic behavior of the wind turbine in adequate details for controller design. This has been done with extensive use of measurements as the basis for selection of model complexity and model validation as well as parameter estimation. The model includes a simple model of the structure of the turbine including tower and flapwise blade bending, a detailed model of the gear box and induction generator, a linearized aerodynamic model including modelling of induction lag and actuator and sensor models. The models are all formulated as linear differential equations. The models are validated through comparisons with measurements performed on a Vestas WD 34 400 kW wind turbine. It is shown from a control point of view simple linear models can be used to describe the dynamic behavior of a pitch controlled wind turbine. The model and the measurements corresponds well in the relevant frequency range. The developed model is therefore applicable for controller design. (au) EFP-91. 18 ills., 22 refs.

  7. Improving fish survival through turbines

    International Nuclear Information System (INIS)

    Ferguson, J.W.

    1993-01-01

    Much of what is known about fish passage through hydroturbines has been developed by studying migratory species of fish passing through large Kaplan turbine units. A review of the literature on previous fish passage research presented in the accompanying story illustrates that studies have focused on determining mortality levels, rather than identifying the causal mechanism involved. There is a need for understanding how turbine designs could be altered to improve fish passage conditions, how to retrofit existing units, and how proposed hydro plant operational changes may affect fish survival. The US Army Corps of Engineers has developed a research program to define biologically based engineering criteria for improving fish passage conditions. Turbine designs incorporating these criteria can be evaluated for their effects on fish survival, engineering issues, costs, and power production. The research program has the following objectives: To gain a thorough knowledge of the mechanisms of fish mortality; To define the biological sensitivities of key fish species to these mechanisms of mortality; To develop new turbine design criteria to reduce fish mortality; To construct prototype turbine designs, and to test these designs for fish passage, hydro-mechanical operation, and power production; and To identify construction and power costs associated with new turbine designs

  8. Lightning protection of wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Soerensen, T; Brask, M H [DEFU (Denmark); Jensen, F V; Raben, N [SEAS (Denmark); Saxov, J [Nordjyllandsvaerket (Denmark); Nielsen, L [Vestkraft (Denmark); Soerensen, P E [Risoe National Lab. (Denmark)

    1999-03-01

    Lightning damage to wind turbines is a serious problem for Danish power companies, who have experienced some cases with very costly lightning damage and a large number of cases with minor damage. The most costly cases include one catastrophic damage to an entire wind turbine, and several cases of destruction of blades, main bearings, generators and control systems. Over the years there have been several hundreds of cases with minor damage - typically damage and interruptions of the control and communication systems, or the power systems. The Danish power companies anticipate that the lightning threat will be even bigger for the large off-shore wind turbine installations that are currently being planned in Denmark. Furthermore, it is known from the off-shore wind turbines at Vindeby in Denmark that the costs of inspection and particularly repair work must be expected to be much higher off-shore as compared to wind turbines on land. These considerations was the background for a two year project concerned with investigation of lighting damages and with the formulation of a DEFU Recommendation for lightning protection of wind turbines, which was published in January 1999. The project was funded by the Danish power companies Elsam, Eltra, Elkraft and by DEFU. (au)

  9. Collecting Currents with Water Turbines

    Science.gov (United States)

    Allen, J.; Allen, S.

    2017-12-01

    Our science poster is inspired by Florida Atlantic University's recent program to develop three types of renewable energy. They are using water turbines and the Gulf Stream Current to produce a renewable energy source. Wave, tidal and current driven energy. Our poster is called "Collecting Currents with Water Turbines". In our science poster, the purpose was to see which turbine design could produce the most power. We tested three different variables, the number of blades (four, six, and eight), the material of the blades and the shape of the blades. To test which number of blades produced the most power we cut slits into a cork. We used plastic from a soda bottle to make the blades and then we put the blades in the cork to make the turbines. We observed each blade and how much time it took for the water turbines to pull up 5 pennies. Currently water turbines are used in dams to make hydroelectric energy. But with FAU we could understand how to harness the Gulf Stream current off Florida's coast we could soon have new forms of renewable energy.

  10. Mechanical and mathematical models of multi-stage horizontal fracturing strings and their application

    Directory of Open Access Journals (Sweden)

    Zhanghua Lian

    2015-03-01

    Full Text Available Multi-stage SRV fracturing in horizontal wells is a new technology developed at home and abroad in recent years to effectively develop shale gas or low-permeability reservoirs, but on the other hand makes the mechanical environment of fracturing strings more complicated at the same time. In view of this, based on the loading features of tubing strings during the multi-stage fracturing of a horizontal well, mechanical models were established for three working cases of multiple packer setting, open differential-pressure sliding sleeve, and open ball-injection sliding sleeve under a hold-down packer. Moreover, mathematical models were respectively built for the above three cases. According to the Lame formula and Von Mises stress calculation formula for the thick-walled cylinder in the theory of elastic mechanics, a mathematical model was also established to calculate the equivalent stress for tubing string safety evaluation when the fracturing string was under the combined action of inner pressure, external squeezing force and axial stress, and another mathematical model was built for the mechanical strength and safety evaluation of multi-stage fracturing strings. In addition, a practical software was developed for the mechanical safety evaluation of horizontal well multi-stage fracturing strings according to the mathematical model developed for the mechanical calculation of the multi-packer string in horizontal wells. The research results were applied and verified in a gas well of Tahe Oilfield in the Tarim Basin with excellent effects, providing a theoretical basis and a simple and reliable technical means for optimal design and safety evaluation of safe operational parameters of multi-stage fracturing strings in horizontal wells.

  11. Model Predictive Control of Wind Turbines

    DEFF Research Database (Denmark)

    Henriksen, Lars Christian

    Wind turbines play a major role in the transformation from a fossil fuel based energy production to a more sustainable production of energy. Total-cost-of-ownership is an important parameter when investors decide in which energy technology they should place their capital. Modern wind turbines...... the need for maintenance of the wind turbine. Either way, better total-cost-of-ownership for wind turbine operators can be achieved by improved control of the wind turbines. Wind turbine control can be improved in two ways, by improving the model on which the controller bases its design or by improving...

  12. Wind turbines and human health.

    Science.gov (United States)

    Knopper, Loren D; Ollson, Christopher A; McCallum, Lindsay C; Whitfield Aslund, Melissa L; Berger, Robert G; Souweine, Kathleen; McDaniel, Mary

    2014-01-01

    The association between wind turbines and health effects is highly debated. Some argue that reported health effects are related to wind turbine operation [electromagnetic fields (EMF), shadow flicker, audible noise, low-frequency noise, infrasound]. Others suggest that when turbines are sited correctly, effects are more likely attributable to a number of subjective variables that result in an annoyed/stressed state. In this review, we provide a bibliographic-like summary and analysis of the science around this issue specifically in terms of noise (including audible, low-frequency noise, and infrasound), EMF, and shadow flicker. Now there are roughly 60 scientific peer-reviewed articles on this issue. The available scientific evidence suggests that EMF, shadow flicker, low-frequency noise, and infrasound from wind turbines are not likely to affect human health; some studies have found that audible noise from wind turbines can be annoying to some. Annoyance may be associated with some self-reported health effects (e.g., sleep disturbance) especially at sound pressure levels >40 dB(A). Because environmental noise above certain levels is a recognized factor in a number of health issues, siting restrictions have been implemented in many jurisdictions to limit noise exposure. These setbacks should help alleviate annoyance from noise. Subjective variables (attitudes and expectations) are also linked to annoyance and have the potential to facilitate other health complaints via the nocebo effect. Therefore, it is possible that a segment of the population may remain annoyed (or report other health impacts) even when noise limits are enforced. Based on the findings and scientific merit of the available studies, the weight of evidence suggests that when sited properly, wind turbines are not related to adverse health. Stemming from this review, we provide a number of recommended best practices for wind turbine development in the context of human health.

  13. Wind turbines and human health

    Directory of Open Access Journals (Sweden)

    Loren eKnopper

    2014-06-01

    Full Text Available The association between wind turbines and health effects is highly debated. Some argue that reported health effects are related to wind turbine operation (electromagnetic fields (EMF, shadow flicker, audible noise, low frequency noise, infrasound. Others suggest that when turbines are sited correctly, effects are more likely attributable to a number of subjective variables that result in an annoyed/stressed state. In this review we provide a bibliographic-like summary and analysis of the science around this issue specifically in terms of noise (including audible, low frequency noise and infrasound, EMF and shadow flicker. Now there are roughly 60 scientific peer-reviewed articles on this issue. The available scientific evidence suggests that EMF, shadow flicker, low frequency noise and infrasound from wind turbines are not likely to affect human health; some studies have found that audible noise from wind turbines can be annoying to some. Annoyance may be associated with some self-reported health effects (e.g., sleep disturbance especially at sound pressure levels >40 dB(A. Because environmental noise above certain levels is a recognized factor in a number of health issues, siting restrictions have been implemented in many jurisdictions to limit noise exposure. These setbacks should help alleviate annoyance from noise. Subjective variables (attitudes and expectations are also linked to annoyance and have the potential to facilitate other health complaints via the nocebo effect. Therefore, it is possible that a segment of the population may remain annoyed (or report other health impacts even when noise limits are enforced. Based on the findings and scientific merit of the available studies, the weight of evidence suggests that when sited properly, wind turbines are not related to adverse health. Stemming from this review, we provide a number of recommended best practices for wind turbine development in the context of human health.

  14. Wind Turbines and Human Health

    Science.gov (United States)

    Knopper, Loren D.; Ollson, Christopher A.; McCallum, Lindsay C.; Whitfield Aslund, Melissa L.; Berger, Robert G.; Souweine, Kathleen; McDaniel, Mary

    2014-01-01

    The association between wind turbines and health effects is highly debated. Some argue that reported health effects are related to wind turbine operation [electromagnetic fields (EMF), shadow flicker, audible noise, low-frequency noise, infrasound]. Others suggest that when turbines are sited correctly, effects are more likely attributable to a number of subjective variables that result in an annoyed/stressed state. In this review, we provide a bibliographic-like summary and analysis of the science around this issue specifically in terms of noise (including audible, low-frequency noise, and infrasound), EMF, and shadow flicker. Now there are roughly 60 scientific peer-reviewed articles on this issue. The available scientific evidence suggests that EMF, shadow flicker, low-frequency noise, and infrasound from wind turbines are not likely to affect human health; some studies have found that audible noise from wind turbines can be annoying to some. Annoyance may be associated with some self-reported health effects (e.g., sleep disturbance) especially at sound pressure levels >40 dB(A). Because environmental noise above certain levels is a recognized factor in a number of health issues, siting restrictions have been implemented in many jurisdictions to limit noise exposure. These setbacks should help alleviate annoyance from noise. Subjective variables (attitudes and expectations) are also linked to annoyance and have the potential to facilitate other health complaints via the nocebo effect. Therefore, it is possible that a segment of the population may remain annoyed (or report other health impacts) even when noise limits are enforced. Based on the findings and scientific merit of the available studies, the weight of evidence suggests that when sited properly, wind turbines are not related to adverse health. Stemming from this review, we provide a number of recommended best practices for wind turbine development in the context of human health. PMID:24995266

  15. High temperature turbine engine structure

    Energy Technology Data Exchange (ETDEWEB)

    Carruthers, W.D.; Boyd, G.L.

    1993-07-20

    A hybrid ceramic/metallic gas turbine is described comprising; a housing defining an inlet, an outlet, and a flow path communicating the inlet with the outlet for conveying a flow of fluid through the housing, a rotor member journaled by the housing in the flow path, the rotor member including a compressor rotor portion rotatively inducting ambient air via the inlet and delivering this air pressurized to the flow path downstream of the compressor rotor, a combustor disposed in the flow path downstream of the compressor receiving the pressurized air along with a supply of fuel to maintain combustion providing a flow of high temperature pressurized combustion products in the flow path downstream thereof, the rotor member including a turbine rotor portion disposed in the flow path downstream of the combustor and rotatively expanding the combustion products toward ambient for flow from the turbine engine via the outlet, the turbine rotor portion providing shaft power driving the compressor rotor portion and an output shaft portion of the rotor member, a disk-like metallic housing portion journaling the rotor member to define a rotational axis therefore, and a disk-like annular ceramic turbine shroud member bounding the flow path downstream of the combustor and circumscribing the turbine rotor portion to define a running clearance therewith, the disk-like ceramic turbine shroud member having a reference axis coaxial with the rotational axis and being spaced axially from the metallic housing portion in mutually parallel concentric relation therewith and a plurality of spacers disposed between ceramic disk-like shroud member and the metallic disk-like housing portion and circumferentially spaced apart, each of the spacers having a first and second end portion having an end surface adjacent the shroud member and the housing portion respectively, the end surfaces having a cylindrical curvature extending transversely relative to the shroud member and the housing portion.

  16. Optimal design of marine steam turbine

    International Nuclear Information System (INIS)

    Liu Chengyang; Yan Changqi; Wang Jianjun

    2012-01-01

    The marine steam turbine is one of the key equipment in marine power plant, and it tends to using high power steam turbine, which makes the steam turbine to be heavier and larger, it causes difficulties to the design and arrangement of the steam turbine, and the marine maneuverability is seriously influenced. Therefore, it is necessary to apply optimization techniques to the design of the steam turbine in order to achieve the minimum weight or volume by means of finding the optimum combination of design parameters. The math model of the marine steam turbine design calculation was established. The sensitivities of condenser pressure, power ratio of HP turbine with LP turbine, and the ratio of diameter with height at the end stage of LP turbine, which influence the weight of the marine steam turbine, were analyzed. The optimal design of the marine steam turbine, aiming at the weight minimization while satisfying the structure and performance constraints, was carried out with the hybrid particle swarm optimization algorithm. The results show that, steam turbine weight is reduced by 3.13% with the optimization scheme. Finally, the optimization results were analyzed, and the steam turbine optimization design direction was indicated. (authors)

  17. Hybrid Turbine Electric Vehicle

    Science.gov (United States)

    Viterna, Larry A.

    1997-01-01

    Hybrid electric power trains may revolutionize today's ground passenger vehicles by significantly improving fuel economy and decreasing emissions. The NASA Lewis Research Center is working with industry, universities, and Government to develop and demonstrate a hybrid electric vehicle. Our partners include Bowling Green State University, the Cleveland Regional Transit Authority, Lincoln Electric Motor Division, the State of Ohio's Department of Development, and Teledyne Ryan Aeronautical. The vehicle will be a heavy class urban transit bus offering double the fuel economy of today's buses and emissions that are reduced to 1/10th of the Environmental Protection Agency's standards. At the heart of the vehicle's drive train is a natural-gas-fueled engine. Initially, a small automotive engine will be tested as a baseline. This will be followed by the introduction of an advanced gas turbine developed from an aircraft jet engine. The engine turns a high-speed generator, producing electricity. Power from both the generator and an onboard energy storage system is then provided to a variable-speed electric motor attached to the rear drive axle. An intelligent power-control system determines the most efficient operation of the engine and energy storage system.

  18. Aircraft gas turbines

    Energy Technology Data Exchange (ETDEWEB)

    Sekido, T [Ishikawajima-Harima Heavy Industries, Co. Ltd., Tokyo (Japan)

    1994-03-01

    Current developmental activities of aircraft gas turbines in Japan are reviewed. V2500-A5 engine with thrust of 30,000 LBF is scheduled to be used for real aircraft in 1994, and intensive developmental activities are also proceeding in larger engines over 90,000 LBF. Recently, developmental programs of engines for 75-100 seat aircraft have been actively discussed, and Japanese engine makers are having discussions towards international collaboration. Such engines will be high bypass turbofans of 12,000-22,000 LBF. Development of SST/HST engines in a speed range from subsonic to Mach 5 is under the initiative of the Agency of Industrial Science and Technology. The Technical Research and Development Institute of Japan, Defence Agency achieved the target thrust of 3.4 tons in the small turbofan engine program, and the small turboshaft engine for small helicopters is also under development. Both National Aerospace Laboratory (NAL) and Institute of Space and Aeronautical Science (ISAS) are now conducting the research programs on turbo-ramjet engines under a component test phase. 1 fig.

  19. Turbines in the ocean

    Science.gov (United States)

    Smith, F. G. W.; Charlier, R. H.

    1981-10-01

    It is noted that the relatively high-speed ocean currents flowing northward along the east coast of the U.S. may be able to supply a significant proportion of the future electric power requirements of urban areas. The Gulf Stream core lies only about 20 miles east of Miami; here its near-surface water reaches velocities of 4.3 miles per hour. Attention is called to the estimate that the energy available in the current of the Gulf Stream adjacent to Florida is approximately equivalent to that generated by 25 1,000-megawatt power plants. It is also contended that this power could be produced at competitive prices during the 1980s using large turbines moored below the ocean surface near the center of the Stream. Assuming an average ocean-current speed between 4 and 5 knots at the current core, the power density of a hydroturbine could reach 410 watts per square foot, about 100 times that of a wind-driven device of similar scale operating in an airflow of approximately 11 knots.

  20. Wind turbine airfoil catalogue

    Energy Technology Data Exchange (ETDEWEB)

    Bertagnolio, F.; Soerensen, N.; Johansen, J.; Fuglsang, P.

    2001-08-01

    The aim of this work is two-sided. Firstly, experimental results obtained for numerous sets of airfoil measurements (mainly intended for wind turbine applications) are collected and compared with computational results from the 2D Navier-Stokes solver EllipSys2D, as well as results from the panel method code XFOIL. Secondly, we are interested in validating the code EllipSys2D and finding out for which air-foils it does not perform well compared to the experiments, as well as why, when it does so. The airfoils are classified according to the agreement between the numerical results and experimental data. A study correlating the available data and this classification is performed. It is found that transition modelling is to a large extent responsible for the poor quality of the computational results for most of the considered airfoils. The transition model mechanism that leads to these discrepancies is identified. Some advices are given for elaborating future airfoil design processes that would involve the numerical code EllipSys2D in particular, and transition modelling in general. (au)

  1. Direct implementation of an axial-flow helium gas turbine tool in a system analysis tool for HTGRs

    International Nuclear Information System (INIS)

    Kim, Ji Hwan; No, Hee Cheon; Kim, Hyeun Min; Lim, Hong Sik

    2008-01-01

    This study concerns the development of dynamic models for a high-temperature gas-cooled reactor (HTGR) through direct implementation of a gas turbine analysis code with a transient analysis code. We have developed a streamline curvature analysis code based on the Newton-Raphson numerical application (SANA) to analyze the off-design performance of helium gas turbines under conditions of normal operation. The SANA code performs a detailed two-dimensional analysis by means of throughflow calculation with allowances for losses in axial-flow multistage compressors and turbines. To evaluate the performance in the steady-state and load transient of HTGRs, we developed GAMMA-T by implementing SANA in the transient system code, GAMMA, which is a multidimensional, multicomponent analysis tool for HTGRs. The reactor, heat exchangers, and connecting pipes were designed with a one-dimensional thermal-hydraulic model that uses the GAMMA code. We assessed GAMMA-T by comparing its results with the steady-state results of the GTHTR300 of JAEA. We concluded that the results are in good agreement, including the results of the vessel cooling bypass flow and the turbine cooling flow

  2. LES investigation of infinite staggered wind-turbine arrays

    International Nuclear Information System (INIS)

    Yang, Xiaolei; Sotiropoulos, Fotis

    2014-01-01

    The layouts of turbines affect the turbine wake interactions and thus the wind farm performance. The wake interactions in infinite staggered wind-turbine arrays are investigated and compared with infinite aligned turbine arrays in this paper. From the numerical results we identify three types of wake behaviours, which are significantly different from wakes in aligned wind-turbine arrays. For the first type, each turbine wake interferes with the pair of staggered downstream turbine wakes and the aligned downstream turbine. For the second type, each turbine wake interacts with the first two downstream turbine wakes but does not show significant interference with the second aligned downstream turbine. For the third type, each turbine wake recovers immediately after passing through the gap of the first two downstream turbines and has little interaction with the second downstream turbine wakes The extracted power density and power efficiency are also studied and compared with aligned wind-turbine arrays

  3. Turbine and its turbine control system of full scope simulator for Qinshan 300 MW Nuclear Power Unit

    International Nuclear Information System (INIS)

    Zhang Dongwei; Zhu Jinping

    1996-01-01

    The simulation for Qinshan 300 MW Nuclear Power Unit turbine and turbine control system is briefly introduced. The simulation system includes lube oil system, jacking oil pump system, turning gear system, turbine supervisor system and turbine control system. It not only correctly simulates the process of turbine normal start up, operation, and shut down, but also the response of turbine under the malfunction conditions

  4. Probabilistic Meteorological Characterization for Turbine Loads

    DEFF Research Database (Denmark)

    Kelly, Mark C.; Larsen, Gunner Chr.; Dimitrov, Nikolay Krasimirov

    2014-01-01

    Beyond the existing, limited IEC prescription to describe fatigue loads on wind turbines, we look towards probabilistic characterization of the loads via analogous characterization of the atmospheric flow, particularly for today's "taller" turbines with rotors well above the atmospheric surface...

  5. Advanced Turbine Blade Cooling Techniques, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Gas turbine engine technology is constantly challenged to operate at higher combustor outlet temperatures. In a modern gas turbine engine, these temperatures can...

  6. Simulating Collisions for Hydrokinetic Turbines

    Energy Technology Data Exchange (ETDEWEB)

    Richmond, Marshall C.; Romero Gomez, Pedro DJ; Rakowski, Cynthia L.

    2013-10-01

    Evaluations of blade-strike on an axial-flow Marine Hydrokinetic turbine were conducted using a conventional methodology as well as an alternative modeling approach proposed in the present document. The proposed methodology integrates the following components into a Computa- tional Fluid Dynamics (CFD) model: (i) advanced eddy-resolving flow simulations, (ii) ambient turbulence based on field data, (iii) moving turbine blades in highly transient flows, and (iv) Lagrangian particles to mimic the potential fish pathways. The sensitivity of blade-strike prob- ability to the following conditions was also evaluated: (i) to the turbulent environment, (ii) to fish size and (iii) to mean stream flow velocity. The proposed methodology provided fraction of collisions and offered the capability of analyzing the causal relationships between the flow envi- ronment and resulting strikes on rotating blades. Overall, the conventional methodology largely overestimates the probability of strike, and lacks the ability to produce potential fish and aquatic biota trajectories as they interact with the rotating turbine. By using a set of experimental corre- lations of exposure-response of living fish colliding on moving blades, the occurrence, frequency and intensity of the particle collisions was next used to calculate the survival rate of fish crossing the MHK turbine. This step indicated survival rates always greater than 98%. Although the proposed CFD framework is computationally more expensive, it provides the advantage of evaluating multiple mechanisms of stress and injury of hydrokinetic turbine devices on fish.

  7. A reference Pelton turbine design

    International Nuclear Information System (INIS)

    Solemslie, B W; Dahlhaug, O G

    2012-01-01

    The designs of hydraulic turbines are usually close kept corporation secrets. Therefore, the possibility of innovation and co-operation between different academic institutions regarding a specific turbine geometry is difficult. A Ph.D.-project at the Waterpower Laboratory, NTNU, aim to design several model Pelton turbines where all measurements, simulations, the design strategy, design software in addition to the physical model will be available to the public. In the following paper a short description of the methods and the test rig that are to be utilized in the project are described. The design will be based on empirical data and NURBS will be used as the descriptive method for the turbine geometry. In addition CFX and SPH simulations will be included in the design process. Each turbine designed and produced in connection to this project will be based on the experience and knowledge gained from the previous designs. The first design will be based on the philosophy to keep a near constant relative velocity through the bucket.

  8. A reference Pelton turbine design

    Science.gov (United States)

    Solemslie, B. W.; Dahlhaug, O. G.

    2012-09-01

    The designs of hydraulic turbines are usually close kept corporation secrets. Therefore, the possibility of innovation and co-operation between different academic institutions regarding a specific turbine geometry is difficult. A Ph.D.-project at the Waterpower Laboratory, NTNU, aim to design several model Pelton turbines where all measurements, simulations, the design strategy, design software in addition to the physical model will be available to the public. In the following paper a short description of the methods and the test rig that are to be utilized in the project are described. The design will be based on empirical data and NURBS will be used as the descriptive method for the turbine geometry. In addition CFX and SPH simulations will be included in the design process. Each turbine designed and produced in connection to this project will be based on the experience and knowledge gained from the previous designs. The first design will be based on the philosophy to keep a near constant relative velocity through the bucket.

  9. Materials for Wind Turbine Blades: An Overview

    DEFF Research Database (Denmark)

    Mishnaevsky, Leon; Branner, Kim; Petersen, Helga Nørgaard

    2017-01-01

    A short overview of composite materials for wind turbine applications is presented here. Requirements toward the wind turbine materials, loads, as well as available materials are reviewed. Apart from the traditional composites for wind turbine blades (glass fibers/epoxy matrix composites), natural...... composites, hybrid and nanoengineered composites are discussed. Manufacturing technologies for wind turbine composites, as well their testing and modelling approaches are reviewed....

  10. Simulation model of nuclear power plant turbine

    International Nuclear Information System (INIS)

    Dutta, Anu; Thangamani, I.; Chakraborty, G.; Ghosh, A.K.

    2006-04-01

    A computer code TURDYN has been developed for prediction of HP and LP turbine torque under thermodynamic transient conditions. The model is based on the conservation laws of mass and energy. All the important components of turbine systems e.g. high pressure turbine, low pressure turbine, feed heaters, reheater, moisture separator have been considered. The details of the mathematical formulation of the model and open loop responses for specific disturbances are presented. (author)

  11. Materials for Wind Turbine Blades: An Overview.

    Science.gov (United States)

    Mishnaevsky, Leon; Branner, Kim; Petersen, Helga Nørgaard; Beauson, Justine; McGugan, Malcolm; Sørensen, Bent F

    2017-11-09

    A short overview of composite materials for wind turbine applications is presented here. Requirements toward the wind turbine materials, loads, as well as available materials are reviewed. Apart from the traditional composites for wind turbine blades (glass fibers/epoxy matrix composites), natural composites, hybrid and nanoengineered composites are discussed. Manufacturing technologies for wind turbine composites, as well their testing and modelling approaches are reviewed.

  12. Repair of steam turbines by welding

    International Nuclear Information System (INIS)

    Bohnstedt, H.J.; Loebert, P.

    1987-01-01

    In some cases, turbine parts can be repaired by welding, even rotating parts such as the shaft or the blades. Practical examples of successful repair work are explained, as for instance: welding of the last web of the turbine wheel of two MD-rotors, repair of erosion damage on turbine blades, of solid-matter erosion on a medium-pressure blading, or welding repair of a high-pressure turbine casing. (DG) [de

  13. Smart Wind Turbine: Analysis and Autonomous Flap

    OpenAIRE

    Bernhammer, L.O.

    2015-01-01

    Wind turbines convert kinetic energy of the wind into electrical energy. Unfortunately, this process is everything but constant, as the wind source shows large fluctuations with high and low frequencies. This turbulence, together with the wind shear and yawed inflow, excites the turbine structure, thereby driving the loads and the design of turbines in general and blades in particular. In response to this, several control mechanisms have been applied to wind turbines since the generation of s...

  14. Calculation of recovery plasticity in multistage hot forging under isothermal conditions.

    Science.gov (United States)

    Zhbankov, Iaroslav G; Perig, Alexander V; Aliieva, Leila I

    2016-01-01

    A widely used method for hot forming steels and alloys, especially heavy forging, is the process of multistage forging with pauses between stages. The well-known effect which accompanies multistage hot forging is metal plasticity recovery in comparison with monotonic deformation. A method which takes into consideration the recovery of plasticity in pauses between hot deformations of a billet under isothermal conditions is proposed. This method allows the prediction of billet forming limits as a function of deformation during the forging stage and the duration of the pause between the stages. This method takes into account the duration of pauses between deformations and the magnitude of subdivided deformations. A hot isothermal upsetting process with pauses was calculated by the proposed method. Results of the calculations have been confirmed with experimental data.

  15. Fractional Multistage Hydrothermal Liquefaction of Biomass and Catalytic Conversion into Hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Cortright, Randy [Virent, Inc., Madison, WI (United States); Rozmiarek, Robert [Virent, Inc., Madison, WI (United States); Dally, Brice [Virent, Inc., Madison, WI (United States); Holland, Chris [Virent, Inc., Madison, WI (United States)

    2017-08-31

    The objective of this project was to develop an improved multistage process for the hydrothermal liquefaction (HTL) of biomass to serve as a new front-end, deconstruction process ideally suited to feed Virent’s well-proven catalytic technology, which is already being scaled up. This process produced water soluble, partially de-oxygenated intermediates that are ideally suited for catalytic finishing to fungible distillate hydrocarbons. Through this project, Virent, with its partners, demonstrated the conversion of pine wood chips to drop-in hydrocarbon distillate fuels using a multi-stage fractional conversion system that is integrated with Virent’s BioForming® process. The majority of work was in the liquefaction task and included temperature scoping, solvent optimization, and separations.

  16. Stage-dependent hierarchy of criteria in multiobjective multistage decision processes

    Directory of Open Access Journals (Sweden)

    Tadeusz Trzaskalik

    2017-01-01

    Full Text Available This paper will consider a multiobjective, multistage discrete dynamic process with a changeable, state-dependent hierarchy of stage criteria determined by the decision maker. The goal of this paper is to answer the question of how to control a multistage process while taking into account both the tendency to achieve multiobjective optimization of the entire process and the time-varying hierarchy of stage criteria. We consider in detail possible situations, where the hierarchy of stage criteria changes over time in individual stages and is stage dependent. We present an interactive proposal to solving the problem, where the decision maker actively participates in finding the final realization of the process. The algorithm proposed is illustrated using a numerical example.

  17. A multi-stage noise adaptive switching filter for extremely corrupted images

    Science.gov (United States)

    Dinh, Hai; Adhami, Reza; Wang, Yi

    2015-07-01

    A multi-stage noise adaptive switching filter (MSNASF) is proposed for the restoration of images extremely corrupted by impulse and impulse-like noise. The filter consists of two steps: noise detection and noise removal. The proposed extrema-based noise detection scheme utilizes the false contouring effect to get better over detection rate at low noise density. It is adaptive and will detect not only impulse but also impulse-like noise. In the noise removal step, a novel multi-stage filtering scheme is proposed. It replaces corrupted pixel with the nearest uncorrupted median to preserve details. When compared with other methods, MSNASF provides better peak signal to noise ratio (PSNR) and structure similarity index (SSIM). A subjective evaluation carried out online also demonstrates that MSNASF yields higher fidelity.

  18. Limitations Of The Current State Space Modelling Approach In Multistage Machining Processes Due To Operation Variations

    Science.gov (United States)

    Abellán-Nebot, J. V.; Liu, J.; Romero, F.

    2009-11-01

    The State Space modelling approach has been recently proposed as an engineering-driven technique for part quality prediction in Multistage Machining Processes (MMP). Current State Space models incorporate fixture and datum variations in the multi-stage variation propagation, without explicitly considering common operation variations such as machine-tool thermal distortions, cutting-tool wear, cutting-tool deflections, etc. This paper shows the limitations of the current State Space model through an experimental case study where the effect of the spindle thermal expansion, cutting-tool flank wear and locator errors are introduced. The paper also discusses the extension of the current State Space model to include operation variations and its potential benefits.

  19. Distributed activation energy model for kinetic analysis of multi-stage hydropyrolysis of coal

    Energy Technology Data Exchange (ETDEWEB)

    Liu, X.; Li, W.; Wang, N.; Li, B. [Chinese Academy of Sciences, Taiyuan (China). Inst. of Coal Chemistry

    2003-07-01

    Based on the new analysis of distributed activation energy model, a bicentral distribution model was introduced to the analysis of multi-stage hydropyrolysis of coal. The hydropyrolysis for linear temperature programming with and without holding stage were mathematically described and the corresponding kinetic expressions were achieved. Based on the kinetics, the hydropyrolysis (HyPr) and multi-stage hydropyrolysis (MHyPr) of Xundian brown coal was simulated. The results shows that both Mo catalyst and 2-stage holding can lower the apparent activation energy of hydropyrolysis and make activation energy distribution become narrow. Besides, there exists an optimum Mo loading of 0.2% for HyPy of Xundian lignite. 10 refs.

  20. The effect of hot multistage drawing on molecular structure and optical properties of polyethylene terephthalate fibers

    Directory of Open Access Journals (Sweden)

    Aminoddin Haji

    2012-08-01

    Full Text Available In this work, mechanical and structural parameters related to the optical properties of polyethylene terephthalate (PET fibers drawn at hot multistage have been investigated. The changes in optical parameters upon changing draw ratio are used to obtain the mechanical orientation factors and , various orientation functions f2(θ, f4(θ and f6(θ, and amorphous and crystalline orientation functions (f a and f c. Also, the numbers of random links between the network junction points (N1, the average optical orientation (Fav, and the distribution function of segment ω(cos θ were calculated. In addition, an empirical formula was suggested to correlate changes in the birefringence with the draw ratio and its constants were determined. The study demonstrated change on the molecular orientation functions and structural parameters upon hot multistage drawing. Significant variations in the characteristic properties of the drawn PET fibers were due to reorientation of the molecules caused by applied heat and external tension.

  1. Comparative study of multistage cemented liner and openhole system completion technologies in the Montney resource play

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Brad; Lui, David; Klim, James [Murphy Oil Company Ltd (United States); Kenyon, Mike [Society of Petroleum Engineers (Canada); McCaffrey, Matt [Packers Plus Energy Services (Canada)

    2011-07-01

    This work highlights hydraulic fracturing technologies implemented in the Lower Montney formation. The goal of the study is to compare two multistage hydraulic fracturing techniques: the cemented liner and the open hole multistage system (OHMS) and to investigate the effects each has on production rates and performance in general. The overall field was separated into two geographical areas and a total of 15 wells were investigated, some of which were subjected to cemented liner fracturing and others to OHMS. Various physical, mechanical, and financial data were collected. These data included: oil production rates, well spacing, pumping rates, stage times, and operational costs. In general, it was shown that OHMS proved to be the more suitable fracturing technique for the Montney formation, yielding higher initial and cumulative production rates. Moreover, average fracturing costs per stage were lower and time to complete was less than with the cemented liner technique.

  2. Continuous-data diagnostic tests for paratuberculosis as a multistage disease

    DEFF Research Database (Denmark)

    Toft, Nils; Nielsen, Søren Saxmose; Jørgensen, Erik

    2005-01-01

    We devised a general method for interpretation of multistage diseases using continuous-data diagnostic tests. As an example, we used paratuberculosis as a multistage infection with 2 stages of infection as well as a noninfected state. Using data from a Danish research project, a fecal culture...... testing scheme was linked to an indirect ELISA and adjusted for covariates (parity, age at first calving, and days in milk). We used the log-transformed optical densities in a Bayesian network to obtain the probabilities for each of the 3 infection stages for a given optical density (adjusted...... for covariates). The strength of this approach was that the uncertainty associated with a test was imposed directly on the individual test result rather than aggregated into the population-based measures of test properties (i.e., sensitivity and specificity)...

  3. Pump Application as Hydraulic Turbine – Pump as Turbine (PaT)

    OpenAIRE

    Rusovs, D

    2009-01-01

    The paper considers pump operation as hydraulic turbine with purpose to produce mechanical power from liquid flow. The Francis hydraulic turbine was selected for comparison with centrifugal pump in reverse operation. Turbine and centrifugal pump velocity triangles were considered with purpose to evaluate PaT efficiency. Shape of impeller blades for turbine and pumps was analysed. Specific speed calculation is carried out with purpose to obtain similarity in pump and turbine description. For ...

  4. ADVANCED TURBINE SYSTEMS PROGRAM

    Energy Technology Data Exchange (ETDEWEB)

    Sy Ali

    2002-03-01

    The market for power generation equipment is undergoing a tremendous transformation. The traditional electric utility industry is restructuring, promising new opportunities and challenges for all facilities to meet their demands for electric and thermal energy. Now more than ever, facilities have a host of options to choose from, including new distributed generation (DG) technologies that are entering the market as well as existing DG options that are improving in cost and performance. The market is beginning to recognize that some of these users have needs beyond traditional grid-based power. Together, these changes are motivating commercial and industrial facilities to re-evaluate their current mix of energy services. One of the emerging generating options is a new breed of advanced fuel cells. While there are a variety of fuel cell technologies being developed, the solid oxide fuel cells (SOFC) and molten carbonate fuel cells (MCFC) are especially promising, with their electric efficiency expected around 50-60 percent and their ability to generate either hot water or high quality steam. In addition, they both have the attractive characteristics of all fuel cells--relatively small siting footprint, rapid response to changing loads, very low emissions, quiet operation, and an inherently modular design lending itself to capacity expansion at predictable unit cost with reasonably short lead times. The objectives of this project are to:(1) Estimate the market potential for high efficiency fuel cell hybrids in the U.S.;(2) Segment market size by commercial, industrial, and other key markets;(3) Identify and evaluate potential early adopters; and(4) Develop results that will help prioritize and target future R&D investments. The study focuses on high efficiency MCFC- and SOFC-based hybrids and competing systems such as gas turbines, reciprocating engines, fuel cells and traditional grid service. Specific regions in the country have been identified where these

  5. A Two-Bladed Concept Wind Turbine

    DEFF Research Database (Denmark)

    Kim, Taeseong

    2012-01-01

    This article shows the potential for reducing extreme loads with an innovative design of wind turbine, a partial pitch two-bladed concept turbine. The most extreme conditions to test a turbine are considered to be stand-still combined with a grid failure in which the wind comes from all directions...

  6. A novel floating offshore wind turbine concept

    DEFF Research Database (Denmark)

    Vita, Luca; Schmidt Paulsen, Uwe; Friis Pedersen, Troels

    2009-01-01

    This paper will present a novel concept of a floating offshore wind turbine. The new concept is intended for vertical-axis wind turbine technology. The main purpose is to increase simplicity and to reduce total costs of an installed offshore wind farm. The concept is intended for deep water...... and large size turbines....

  7. Nonlinear Dynamics of Wind Turbine Wings

    DEFF Research Database (Denmark)

    Larsen, Jesper Winther

    , large wind turbines become increasingly flexible and dynamically sensitive. This project focuses on the structural analysis of highly flexible wind turbine wings, and the aerodynamic loading of wind turbine wings under large changes in flow field due to elastic deformations and changing wind conditions....

  8. Ducted wind turbine optimization : A numerical approach

    NARCIS (Netherlands)

    Dighe, V.V.; De Oliveira Andrade, G.L.; van Bussel, G.J.W.

    2017-01-01

    The practice of ducting wind turbines has shown a beneficial effect on the overall performance, when compared to an open turbine of the same rotor diameter1. However, an optimization study specifically for ducted wind turbines (DWT’s) is missing or incomplete. This work focuses on a numerical

  9. Wind turbine with lightning protection system

    DEFF Research Database (Denmark)

    2016-01-01

    The present invention relates to a wind turbine comprising a lightning protection system comprising a waveguide interconnecting a communication device and a signal-carrying structure. In other aspects, the present invention relates to the use of a waveguide in a lightning protection system...... of a wind turbine, a power splitter and its use in a lightning protection system of a wind turbine....

  10. Performance and safety of hydraulic turbines

    International Nuclear Information System (INIS)

    Brekke, H

    2010-01-01

    The first part of the paper contains the choice of small turbines for run of the river power plants. Then a discussion is given on the optimization of the performance of different types of large turbines. Finally a discussion on the safety and necessary maintenance of turbines is given with special attention to bolt connections.

  11. Development of Low Price Turbine Control System

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, C.K.; Kim, J.A.; Jeong, W.J.; Choi, I.K.; Woo, J.H. [Korea Electric Power Research Institute, Taejon (Korea)

    2002-07-01

    This report is final research results of ''Development of Low Price Turbine Control System''. It describes test such as turbine startup, generator synchronization, rated load operation, simulation after manufacturing turbine control system. (author). 45 figs., 11 tabs.

  12. Microprocessor control of a wind turbine generator

    Science.gov (United States)

    Gnecco, A. J.; Whitehead, G. T.

    1978-01-01

    This paper describes a microprocessor based system used to control the unattended operation of a wind turbine generator. The turbine and its microcomputer system are fully described with special emphasis on the wide variety of tasks performed by the microprocessor for the safe and efficient operation of the turbine. The flexibility, cost and reliability of the microprocessor were major factors in its selection.

  13. Heat Transfer in Gas Turbines

    Science.gov (United States)

    Garg, Vijay K.

    2001-01-01

    The turbine gas path is a very complex flow field. This is due to a variety of flow and heat transfer phenomena encountered in turbine passages. This manuscript provides an overview of the current work in this field at the NASA Glenn Research Center. Also, based on the author's preference, more emphasis is on the computational work. There is much more experimental work in progress at GRC than that reported here. While much has been achieved, more needs to be done in terms of validating the predictions against experimental data. More experimental data, especially on film cooled and rough turbine blades, are required for code validation. Also, the combined film cooling and internal cooling flow computation for a real blade is yet to be performed. While most computational work to date has assumed steady state conditions, the flow is clearly unsteady due to the presence of wakes. All this points to a long road ahead. However, we are well on course.

  14. Vertical axis wind turbine airfoil

    Science.gov (United States)

    Krivcov, Vladimir; Krivospitski, Vladimir; Maksimov, Vasili; Halstead, Richard; Grahov, Jurij Vasiljevich

    2012-12-18

    A vertical axis wind turbine airfoil is described. The wind turbine airfoil can include a leading edge, a trailing edge, an upper curved surface, a lower curved surface, and a centerline running between the upper surface and the lower surface and from the leading edge to the trailing edge. The airfoil can be configured so that the distance between the centerline and the upper surface is the same as the distance between the centerline and the lower surface at all points along the length of the airfoil. A plurality of such airfoils can be included in a vertical axis wind turbine. These airfoils can be vertically disposed and can rotate about a vertical axis.

  15. Reliability Modeling of Wind Turbines

    DEFF Research Database (Denmark)

    Kostandyan, Erik

    Cost reductions for offshore wind turbines are a substantial requirement in order to make offshore wind energy more competitive compared to other energy supply methods. During the 20 – 25 years of wind turbines useful life, Operation & Maintenance costs are typically estimated to be a quarter...... for Operation & Maintenance planning. Concentrating efforts on development of such models, this research is focused on reliability modeling of Wind Turbine critical subsystems (especially the power converter system). For reliability assessment of these components, structural reliability methods are applied...... to one third of the total cost of energy. Reduction of Operation & Maintenance costs will result in significant cost savings and result in cheaper electricity production. Operation & Maintenance processes mainly involve actions related to replacements or repair. Identifying the right times when...

  16. Endoscopic inspection of steam turbines

    International Nuclear Information System (INIS)

    Maliniemi, H.; Muukka, E.

    1990-01-01

    For over ten years, Imatran Voima Oy (IVO) has developed, complementary inspection methods for steam turbine condition monitoring, which can be applied both during operation and shutdown. One important method used periodically during outages is endoscopic inspection. The inspection is based on the method where the internal parts of the turbine is inspected through access borings with endoscope and where the magnified figures of the internal parts is seen on video screen. To improve inspection assurance, an image-processing based pattern recognition method for cracks has been developed for the endoscopic inspection of turbine blades. It is based on the deduction conditions derived from the crack shape. The computer gives an alarm of a crack detection and prints a simulated image of the crack, which is then checked manually

  17. Type IV Wind Turbine Model

    DEFF Research Database (Denmark)

    Hansen, Anca Daniela; Margaris, Ioannis D.

    . In the project, this wind turbine model will be further incorporated in a wind power plant model together with the implementation in the wind power control level of the new control functionalities (inertial response, synchronising power and power system damping). For this purpose an aggregate wind power plant......This document is created as part of the EaseWind project. The goal of this project is to develop and investigate new control features for primary response provided by wind power plants. New control features as inertial response, synchronising power and power system damping are of interest to EaseWind...... project to be incorporated in the wind power plant level. This document describes the Type 4 wind turbine simulation model, implemented in the EaseWind project. The implemented wind turbine model is one of the initial necessary steps toward integrating new control services in the wind power plant level...

  18. Waste heat gas utilization for HTGR gas turbine plant for sea water desalination

    International Nuclear Information System (INIS)

    Hunter, D.A.A.

    1981-01-01

    A thermodynamic analysis is performed for a HTGR - Gas Turbine Plant, coupled with a Rankine cycle for additional power generation and/or desalination of sea water with a multistage flash evaporator. Three basic alternatives are studied: a) Brayton cycle with inter-cooling and without regeneration, coupled with a Rankine cycle for power generation and steam for evaporator. b) Same as a) but without inter-cooling and with regeneration. c) Brayton cycle with regeneration, without inter-cooling, coupled with a Rankine cycle for sea water evaporator steam generation. The behavior of the three alternatives is established with a parametric study for the most representative variables. Economy, safety and control aspects were considered for the three different conceptions. (Author) [pt

  19. Threat Assessment for Multistage Cyber Attacks in Smart Grid Communication Networks

    OpenAIRE

    He, Xiaobing

    2017-01-01

    In smart grids, managing and controlling power operations are supported by information and communication technology (ICT) and supervisory control and data acquisition (SCADA) systems. The increasing adoption of new ICT assets in smart grids is making smart grids vulnerable to cyber threats, as well as raising numerous concerns about the adequacy of current security approaches. As a single act of penetration is often not sufficient for an attacker to achieve his/her goal, multistage cyb...

  20. Multistage electrodeposition of supported platinum-based nanostructured systems for electrocatalytic applications

    CSIR Research Space (South Africa)

    Mkwizu, TS

    2011-05-01

    Full Text Available .R. Modibedi and Mkhulu K. Mathe* *kmathe@csir.co.za 219th ECS Meeting, 1 ? 6 May, 2011, Montreal, Canada Multistage Electrodeposition of Supported Platinum-based Nanostructured Systems for Electrocatalytic Applications Overview ? Acknowledgements... of constituent elements of the given electrode surface. ? Applications areas: Fuel cells, electrochemical sensors, electrolyzers Introduction e- A B 5 Introduction Atomic-level processes during electrocatalysis www...

  1. Multi-stage Optimization of Matchings in Trees with Application to Kidney Exchange

    KAUST Repository

    Mankowski, Michal

    2017-07-22

    In this paper, we propose a method for multi-stage optimization of matchings in trees relative to different weight functions that assign positive weights to the edges of the trees. This method can be useful in transplantology where nodes of the tree correspond to pairs (donor, recipient) and two nodes (pairs) are connected by an edge if these pairs can exchange kidneys. Weight functions can characterize the number of exchanges, the importance of exchanges, or their compatibility.

  2. Multi-stage LLC resonant converters designed for wide output voltage ranges

    OpenAIRE

    Tsang, C.-W.; Bingham, C. M.; Foster, M. P.; Stone, D. A.; Leech, J. M.

    2016-01-01

    The paper describes a novel multi-stage LLC resonant converter topology for facilitating wide output voltage ranges. This is achieved by combining the gain range of a capacitor-diode clamped LLC resonant converter with that of a traditional LLC resonant converter. A prototype converter is designed and commissioned to illustrate the design procedure and demonstrate resulting operational characteristics. Experimental results are used to show operational characteristics of the proposed conver...

  3. Multi-stage phase retrieval algorithm based upon the gyrator transform.

    Science.gov (United States)

    Rodrigo, José A; Duadi, Hamootal; Alieva, Tatiana; Zalevsky, Zeev

    2010-01-18

    The gyrator transform is a useful tool for optical information processing applications. In this work we propose a multi-stage phase retrieval approach based on this operation as well as on the well-known Gerchberg-Saxton algorithm. It results in an iterative algorithm able to retrieve the phase information using several measurements of the gyrator transform power spectrum. The viability and performance of the proposed algorithm is demonstrated by means of several numerical simulations and experimental results.

  4. Multi-stage phase retrieval algorithm based upon the gyrator transform

    OpenAIRE

    Rodrigo Martín-Romo, José Augusto; Duadi, Hamootal; Alieva, Tatiana Krasheninnikova; Zalevsky, Zeev

    2010-01-01

    The gyrator transform is a useful tool for optical information processing applications. In this work we propose a multi-stage phase retrieval approach based on this operation as well as on the well-known Gerchberg-Saxton algorithm. It results in an iterative algorithm able to retrieve the phase information using several measurements of the gyrator transform power spectrum. The viability and performance of the proposed algorithm is demonstrated by means of several numerical simulations and exp...

  5. Hydrodynamic and mechanical tests of a newly improved counter-current multi-stage centrifugal extractor

    International Nuclear Information System (INIS)

    Ionita, Gheorghe; Mirica, Dumitru; Croitoru, Cornelia; Stefanescu, Ioan; Retegan, Teodora

    2003-01-01

    Total actinide recovery, lanthanide/actinide separation and the selective partitioning of actinide from high level waste (HLW) are nowadays of major interest. Actinide partitioning with a view to safe disposing of HLW or utilization in many other applications of recovered elements involves an extraction process usually carried out by means of a mixer-settler, pulse column or centrifugal contactor. This last, presents some doubtless advantages and responds to the above mentioned goals. A new type of counter-current multistage centrifugal extractor has been designed and built. Similar apparatus was not found in the literature published to-date. The counter-current multi-stage centrifugal extractor is a stainless steel cylinder with an effective length of 346 mm, the effective diameter of 100 mm and a volume of 1.5 liters, working in horizontal position. The new internal structure and geometry of the new advanced centrifugal extractor consisting of nine cells (units), five rotation units, two mixing units, two propelling units and two final plates, ensures the counter-current running of the two phases.The central shaft having the rotation cells fixed on it is coupled by an intermediary connection to a electric motor of high rotation speed. Conceptual layout of the advanced counter-current multi-stage centrifugal extractor is presented. The newly designed extractor has been tested at 1000-3000 rot/min for a ratio of the aqueous/organic phase =1 to examine the mechanical behavior and the hydrodynamics of the two phases in countercurrent. The results showed that the performances have been generally good and the design requirements were fulfilled. The newly designed counter-current multistage centrifugal extractor appears to be a promising way to increase extraction rate of radionuclides and metals from liquid effluents. (authors)

  6. Multi-stage pulsed laser deposition of aluminum nitride at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Duta, L. [National Institute for Lasers, Plasma, and Radiation Physics, 409 Atomistilor Street, 077125 Magurele (Romania); Stan, G.E. [National Institute of Materials Physics, 105 bis Atomistilor Street, 077125 Magurele (Romania); Stroescu, H.; Gartner, M.; Anastasescu, M. [Institute of Physical Chemistry “Ilie Murgulescu”, Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest (Romania); Fogarassy, Zs. [Research Institute for Technical Physics and Materials Science, Hungarian Academy of Sciences, Konkoly Thege Miklos u. 29-33, H-1121 Budapest (Hungary); Mihailescu, N. [National Institute for Lasers, Plasma, and Radiation Physics, 409 Atomistilor Street, 077125 Magurele (Romania); Szekeres, A., E-mail: szekeres@issp.bas.bg [Institute of Solid State Physics, Bulgarian Academy of Sciences, Tzarigradsko Chaussee 72, Sofia 1784 (Bulgaria); Bakalova, S. [Institute of Solid State Physics, Bulgarian Academy of Sciences, Tzarigradsko Chaussee 72, Sofia 1784 (Bulgaria); Mihailescu, I.N., E-mail: ion.mihailescu@inflpr.ro [National Institute for Lasers, Plasma, and Radiation Physics, 409 Atomistilor Street, 077125 Magurele (Romania)

    2016-06-30

    Highlights: • Multi-stage pulsed laser deposition of aluminum nitride at different temperatures. • 800 °C seed film boosts the next growth of crystalline structures at lower temperature. • Two-stage deposited AlN samples exhibit randomly oriented wurtzite structures. • Band gap energy values increase with deposition temperature. • Correlation was observed between single- and multi-stage AlN films. - Abstract: We report on multi-stage pulsed laser deposition of aluminum nitride (AlN) on Si (1 0 0) wafers, at different temperatures. The first stage of deposition was carried out at 800 °C, the optimum temperature for AlN crystallization. In the second stage, the deposition was conducted at lower temperatures (room temperature, 350 °C or 450 °C), in ambient Nitrogen, at 0.1 Pa. The synthesized structures were analyzed by grazing incidence X-ray diffraction (GIXRD), transmission electron microscopy (TEM), atomic force microscopy and spectroscopic ellipsometry (SE). GIXRD measurements indicated that the two-stage deposited AlN samples exhibited a randomly oriented wurtzite structure with nanosized crystallites. The peaks were shifted to larger angles, indicative for smaller inter-planar distances. Remarkably, TEM images demonstrated that the high-temperature AlN “seed” layers (800 °C) promoted the growth of poly-crystalline AlN structures at lower deposition temperatures. When increasing the deposition temperature, the surface roughness of the samples exhibited values in the range of 0.4–2.3 nm. SE analyses showed structures which yield band gap values within the range of 4.0–5.7 eV. A correlation between the results of single- and multi-stage AlN depositions was observed.

  7. A Systematic Approach to Quality Oriented Product Sequencing for Multistage Manufacturing Systems

    OpenAIRE

    Zhang, Faping; Butt, Shahid Ikramullah

    2016-01-01

    Product sequencing is one way to reduce cost and improve product quality for multistage manufacturing systems (MMS). However, systematically evaluating the influence of product sequence on quality performance for MMS is still a challenge. By considering the rate of incoming conforming product, manufacturing system quality transition between batch to batch, and quality propagation along stages, this paper investigates the appropriate batch policies and product sequencing for MMS so that satisf...

  8. Il ritorno di Bertoldo. Il campionamento multi-stage a raggio d’azione

    OpenAIRE

    Catania, Danilo

    2016-01-01

    The article proposes a new multi-stage sampling procedure in face to face surveys at national and regional level. This proposal foresees to assign to each interviewer a range of action where to realise their interviews, thus widening their concerning area, which isn’t anymore identifiable with a sampling point (often corresponding to the interviewer’s residence municipality), but with a sampling area where n municipalities are located and may be reached by the interviewer. The idea is to pass...

  9. Investments in the LNG Value Chain: A Multistage Stochastic Optimization Model focusing on Floating Liquefaction Units

    OpenAIRE

    Røstad, Lars Dybsjord; Erichsen, Jeanette Christine

    2012-01-01

    In this thesis, we have developed a strategic optimization model of investments in infrastructure in the LNG value chain. The focus is on floating LNG production units: when they are a viable solution and what value they add to the LNG value chain. First a deterministic model is presented with focus on describing the value chain, before it is expanded to a multistage stochastic model with uncertain field sizes and gas prices. The objective is to maximize expected discounted profits through op...

  10. Multiwire proportional chamber and multistage avalanche chamber with low concentration photoionization gas

    International Nuclear Information System (INIS)

    Zhao Pingde; Xu Zhiqing; Tang Xiaowei

    1986-01-01

    The characteristics of multiwire proportional chamber and multistage avalanche chamber filled with argon and photoionization gas (C 2 H 5 ) 3 N were measured. The spatial resolution curves and output pulse height spectra were measured as well. Low concentration (C 2 H 5 ) 3 N can play an effective part in quenching. At very low concentration, the phenomena of avalanche transverse expansion was observed obviously

  11. New improved counter - current multi-stage centrifugal extractor for solvent extraction process

    International Nuclear Information System (INIS)

    Gheorghe, Ionita; Mirica, Dumitru; Croitoru, Cornelia; Stefanescu, Ioan; Retegan, Teodora; Kitamoto, Asashi

    2003-01-01

    Total actinide recovery, lanthanide/actinide separation and selective partitioning of actinide from high level waste (HLW) are nowadays of a major interest. Actinide partitioning with a view to safe disposing of HLW or utilization in many other applications of recovered elements involves an extraction process usually by means of mixer-settler, pulse column or centrifugal contactor. The latter, presents some doubtless advantages and responds to the above mentioned goals. A new type of counter-current multistage centrifugal extractor has been designed and performed. A similar apparatus was not found from in other published papers as yet. The counter-current multi-stage centrifugal extractor was a cylinder made of stainless steel with an effective length of 346 mm, the effective diameter of 100 mm and a volume of 1.5 liters, working in a horizontal position. The new internal structure and geometry of the new advanced centrifugal extractor consisting of nine cells (units), five rotation units, two mixing units, two propelling units and two final plates, ensures the counter-current running of the two phases.The central shaft having the rotation cells fixed on it is coupled by an intermediary connection to a electric motor of high rotation speed. The conceptual layout of the advanced counter-current multi-stage centrifugal extractor is presented. The newly designed extractor has been tested at 500-2800 rot/min for a ratio of the aqueous/organic phase =1 to examine the mechanical behavior and the hydrodynamics of the two phases in countercurrent. The results showed that the performances have been generally good and the design requirements were fulfilled. The newly designed counter-current multistage centrifugal extractor appears to be a promising way to increase extraction rate of radionuclides and metals from liquid effluents. (authors)

  12. A Multistage Sulphidisation Flotation Procedure for a Low Grade Malachite Copper Ore

    OpenAIRE

    Tebogo P. Phetla; Edison Muzenda

    2010-01-01

    This study was carried out to develop a flotation procedure for an oxide copper ore from a Region in Central Africa for producing an 18% copper concentrate for downstream processing at maximum recovery from a 4% copper feed grade. The copper recoveries achieved from the test work were less than 50% despite changes in reagent conditions (multistage sulphidisation, use of RCA emulsion and mixture, use of AM 2, etc). The poor recoveries were attributed to the mineralogy of t...

  13. Multi-stage selective catalytic reduction of NOx in lean burn engine exhaust

    Energy Technology Data Exchange (ETDEWEB)

    Penetrante, B.M.; Hsaio, M.C.; Merritt, B.T.; Vogtlin, G.E. [Lawrence Livermore National Lab., CA (United States)

    1997-12-31

    Many studies suggest that the conversion of NO to NO{sub 2} is an important intermediate step in the selective catalytic reduction (SCR) of NO{sub x} to N{sub 2}. Some effort has been devoted to separating the oxidative and reductive functions of the catalyst in a multi-stage system. This method works fine for systems that require hydrocarbon addition. The hydrocarbon has to be injected between the NO oxidation catalyst and the NO{sub 2} reduction catalyst; otherwise, the first-stage oxidation catalyst will also oxidize the hydrocarbon and decrease its effectiveness as a reductant. The multi-stage catalytic scheme is appropriate for diesel engine exhausts since they contain insufficient hydrocarbons for SCR, and the hydrocarbons can be added at the desired location. For lean-burn gasoline engine exhausts, the hydrocarbons already present in the exhausts will make it necessary to find an oxidation catalyst that can oxidize NO to NO{sub 2} but not oxidize the hydrocarbon. A plasma can also be used to oxidize NO to NO{sub 2}. Plasma oxidation has several advantages over catalytic oxidation. Plasma-assisted catalysis can work well for both diesel engine and lean-burn gasoline engine exhausts. This is because the plasma can oxidize NO in the presence of hydrocarbons without degrading the effectiveness of the hydrocarbon as a reductant for SCR. In the plasma, the hydrocarbon enhances the oxidation of NO, minimizes the electrical energy requirement, and prevents the oxidation of SO{sub 2}. This paper discusses the use of multi-stage systems for selective catalytic reduction of NO{sub x}. The multi-stage catalytic scheme is compared to the plasma-assisted catalytic scheme.

  14. A surrogate based multistage-multilevel optimization procedure for multidisciplinary design optimization

    OpenAIRE

    Yao, W.; Chen, X.; Ouyang, Q.; Van Tooren, M.

    2011-01-01

    Optimization procedure is one of the key techniques to address the computational and organizational complexities of multidisciplinary design optimization (MDO). Motivated by the idea of synthetically exploiting the advantage of multiple existing optimization procedures and meanwhile complying with the general process of satellite system design optimization in conceptual design phase, a multistage-multilevel MDO procedure is proposed in this paper by integrating multiple-discipline-feasible (M...

  15. Multi-stage volcanic island flank collapses with coeval explosive caldera-forming eruptions

    OpenAIRE

    Hunt, James E.; Cassidy, Michael; Talling, Peter J.

    2018-01-01

    Volcanic flank collapses and explosive eruptions are among the largest and most destructive processes on Earth. Events at Mount St. Helens in May 1980 demonstrated how a relatively small (<5 km3) flank collapse on a terrestrial volcano could immediately precede a devastating eruption. The lateral collapse of volcanic island flanks, such as in the Canary Islands, can be far larger (>300 km3), but can also occur in complex multiple stages. Here, we show that multistage retrogressive lands...

  16. Numerical Analysis of Unsteady Cavitating Flow around Balancing Drum of Multistage Pump

    Czech Academy of Sciences Publication Activity Database

    Sedlář, M.; Krátký, T.; Zima, Patrik

    2016-01-01

    Roč. 9, č. 2 (2016), s. 119-128 ISSN 1882-9554. [Asian International Conference on Fluid Machinery /13./ (AICFM. Tokyo, 07.09.2015-10.09.2015] R&D Projects: GA ČR GA13-23550S Institutional support: RVO:61388998 Keywords : cavitation erosion * numerical simulation * multistage pump Subject RIV: BK - Fluid Dynamics https://www.jstage.jst.go.jp/article/ijfms/9/2/9_119/_article

  17. Aerodynamic Analysis and Three-Dimensional Redesign of a Multi-Stage Axial Flow Compressor

    Directory of Open Access Journals (Sweden)

    Tao Ning

    2016-04-01

    Full Text Available This paper describes the introduction of three-dimension (3-D blade designs into a 5-stage axial compressor with multi-stage computational fluid dynamic (CFD methods. Prior to a redesign, a validation study is conducted for the overall performance and flow details based on full-scale test data, proving that the multi-stage CFD applied is a relatively reliable tool for the analysis of the follow-up redesign. Furthermore, at the near stall point, the aerodynamic analysis demonstrates that significant separation exists in the last stator, leading to the aerodynamic redesign, which is the focus of the last stator. Multi-stage CFD methods are applied throughout the three-dimensional redesign process for the last stator to explore their aerodynamic improvement potential. An unconventional asymmetric bow configuration incorporated with leading edge re-camber and re-solidity is employed to reduce the high loss region dominated by the mainstream. The final redesigned version produces a 13% increase in the stall margin while maintaining the efficiency at the design point.

  18. Development of JSTAMP-Works/NV and HYSTAMP for Multipurpose Multistage Sheet Metal Forming Simulation

    International Nuclear Information System (INIS)

    Umezu, Yasuyoshi; Watanabe, Yuko; Ma, Ninshu

    2005-01-01

    Since 1996, Japan Research Institute Limited (JRI) has been providing a sheet metal forming simulation system called JSTAMP-Works packaged the FEM solvers of LS-DYNA and JOH/NIKE, which might be the first multistage system at that time and has been enjoying good reputation among users in Japan. To match the recent needs, 'faster, more accurate and easier', of process designers and CAE engineers, a new metal forming simulation system JSTAMP-Works/NV is developed. The JSTAMP-Works/NV packaged the automatic healing function of CAD and had much more new capabilities such as prediction of 3D trimming lines for flanging or hemming, remote control of solver execution for multi-stage forming processes and shape evaluation between FEM and CAD.On the other way, a multi-stage multi-purpose inverse FEM solver HYSTAMP is developed and will be soon put into market, which is approved to be very fast, quite accurate and robust.Lastly, authors will give some application examples of user defined ductile damage subroutine in LS-DYNA for the estimation of material failure and springback in metal forming simulation

  19. Development of JSTAMP-Works/NV and HYSTAMP for Multipurpose Multistage Sheet Metal Forming Simulation

    Science.gov (United States)

    Umezu, Yasuyoshi; Watanabe, Yuko; Ma, Ninshu

    2005-08-01

    Since 1996, Japan Research Institute Limited (JRI) has been providing a sheet metal forming simulation system called JSTAMP-Works packaged the FEM solvers of LS-DYNA and JOH/NIKE, which might be the first multistage system at that time and has been enjoying good reputation among users in Japan. To match the recent needs, "faster, more accurate and easier", of process designers and CAE engineers, a new metal forming simulation system JSTAMP-Works/NV is developed. The JSTAMP-Works/NV packaged the automatic healing function of CAD and had much more new capabilities such as prediction of 3D trimming lines for flanging or hemming, remote control of solver execution for multi-stage forming processes and shape evaluation between FEM and CAD. On the other way, a multi-stage multi-purpose inverse FEM solver HYSTAMP is developed and will be soon put into market, which is approved to be very fast, quite accurate and robust. Lastly, authors will give some application examples of user defined ductile damage subroutine in LS-DYNA for the estimation of material failure and springback in metal forming simulation.

  20. Time stamp technique using a nuclear emulsion multi-stage shifter for gamma-ray telescope

    International Nuclear Information System (INIS)

    Takahashi, Satoru; Aoki, Shigeki; Rokujo, Hiroki; Hamada, Kaname; Komatsu, Masahiro; Morishima, Kunihiro; Nakamura, Mitsuhiro; Nakano, Toshiyuki; Niwa, Kimio; Sato, Osamu; Yoshioka, Teppei; Kodama, Koichi

    2010-01-01

    Nuclear emulsion has a potential use as a gamma-ray telescope with high angular resolution. For this application it is necessary to know the time when each track was recorded in the emulsion. In previous experiments using nuclear emulsion, various efforts were used to associate time to nuclear emulsion tracks and to improve the time resolution. Using a high speed readout system for nuclear emulsion together with a clock-based multi-stage emulsion shifter, we invented a technique to give a time-stamp to emulsion tracks and greatly improve the time resolution. A test experiment with a 2-stage shifter was used to demonstrate the principle of multi-stage shifting, and we achieved a time resolution 1.5 s for 12.1 h (about 1 part in 29 000) with the time stamp reliability 97% and the time stamp efficiency 98%. This multi-stage shifter can achieve the time resolution required for a gamma-ray telescope and can also be applied to another cosmic ray observations and accelerator experiments using nuclear emulsion.

  1. Inexact Multistage Stochastic Chance Constrained Programming Model for Water Resources Management under Uncertainties

    Directory of Open Access Journals (Sweden)

    Hong Zhang

    2017-01-01

    Full Text Available In order to formulate water allocation schemes under uncertainties in the water resources management systems, an inexact multistage stochastic chance constrained programming (IMSCCP model is proposed. The model integrates stochastic chance constrained programming, multistage stochastic programming, and inexact stochastic programming within a general optimization framework to handle the uncertainties occurring in both constraints and objective. These uncertainties are expressed as probability distributions, interval with multiply distributed stochastic boundaries, dynamic features of the long-term water allocation plans, and so on. Compared with the existing inexact multistage stochastic programming, the IMSCCP can be used to assess more system risks and handle more complicated uncertainties in water resources management systems. The IMSCCP model is applied to a hypothetical case study of water resources management. In order to construct an approximate solution for the model, a hybrid algorithm, which incorporates stochastic simulation, back propagation neural network, and genetic algorithm, is proposed. The results show that the optimal value represents the maximal net system benefit achieved with a given confidence level under chance constraints, and the solutions provide optimal water allocation schemes to multiple users over a multiperiod planning horizon.

  2. Analysis of multistage chains in public transport: The case of Quito, Ecuador

    Energy Technology Data Exchange (ETDEWEB)

    Bastidas Zelaya, E.

    2016-07-01

    Because of the growth of cities in size and population, people get used to perform several stage trips involving transfers due to advantages such as time or price paid, being multistage trips more attractive compared to single stage trips. In Quito, Ecuador, nowadays multistage trips represent one third of total daily trips. This paper seeks to identify main characteristics of multistage trips as well as find relationships and inferences that allow recommendations regarding best practices to policy makers and transport managers. The information used belong to the data collected in the Household Survey Mobility held in Quito in 2011. Based on these data, the present work starts using an analysis with descriptive statistics. The next phase of this research involves the search for a methodology in order to identify correlations between demographic, socioeconomic and transport variables related with traveler´s choice for making or not a transfer. Best methodology found was the use of Binary Logistic Regression (Logit) and specific computer software, with which different statistic's models were performed to find the strongest correlation. The paper ends with conclusions and recommendations as well as suggestions for future research. (Author)

  3. A development of time-resolved emulsion detector by multi-stage shifter

    International Nuclear Information System (INIS)

    Takahashi, Satoru; Aoki, Shigeki

    2017-01-01

    Nuclear emulsion is a powerful tracking device that can record the three-dimensional trajectory of charged particles within 1 μm spatial resolution. We are promoting GRAINE project which is 10 MeV-100 GeV cosmic γ-ray observations with a precise (0.08deg at 1-2 GeV) and polarization-sensitive large-aperture-area (∼10 m 2 ) emulsion telescope by repeating long duration balloon flights. We are developing multi-stage shifter which allows us to give a timing information to emulsion tracks with ∼seconds or below. The multi-stage shifter opened feasibilities of precise cosmic γ-ray observations, GRAINE, as well as precise measurements of ν-N interactions, J-PARC T60. ∼Millisecond time resolution in a balloon-borne experiment, ∼second time resolution for 126.7 days in an accelerator ν experiment and ∼10 6 time-resolved numbers are being achieved. New model of multi-stage shifter is also being developed for future experiments. (author)

  4. Health condition identification of multi-stage planetary gearboxes using a mRVM-based method

    Science.gov (United States)

    Lei, Yaguo; Liu, Zongyao; Wu, Xionghui; Li, Naipeng; Chen, Wu; Lin, Jing

    2015-08-01

    Multi-stage planetary gearboxes are widely applied in aerospace, automotive and heavy industries. Their key components, such as gears and bearings, can easily suffer from damage due to tough working environment. Health condition identification of planetary gearboxes aims to prevent accidents and save costs. This paper proposes a method based on multiclass relevance vector machine (mRVM) to identify health condition of multi-stage planetary gearboxes. In this method, a mRVM algorithm is adopted as a classifier, and two features, i.e. accumulative amplitudes of carrier orders (AACO) and energy ratio based on difference spectra (ERDS), are used as the input of the classifier to classify different health conditions of multi-stage planetary gearboxes. To test the proposed method, seven health conditions of a two-stage planetary gearbox are considered and vibration data is acquired from the planetary gearbox under different motor speeds and loading conditions. The results of three tests based on different data show that the proposed method obtains an improved identification performance and robustness compared with the existing method.

  5. Rotary turbine for reduced flows

    Energy Technology Data Exchange (ETDEWEB)

    Florio, G.; Scornaienchi, N.M. (Calabria Univ., Arcavacata di Rende (Italy). Dipt. di Meccanica)

    1988-06-01

    The principal characteristics of the steam turbine are its simple design (and therefore low fabrication cost) and capability of handling very small rates in the order grams/s. Another important characteristic is that the deflector channel receives fluid without incidence for any value of relative velocity. This allows for a wider field of application as compared with bladed turbines. Taking into account losses due to the fact that the fluid works at relatively high velocities for long sections and to fluid leakage, efficiencies have been estimated at about 40%.

  6. Noise from offshore wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Soendergaard, B.; Plovsing, B.

    2005-07-01

    Noise assessment of wind turbines through calculations is based on sound power levels measured according to e.g. IEC 61400-11. With larger wind turbines and distances some of the calculation models give erroneous results. Noise propagation over water is different from propagation over land. For that reason it is important be able to make valid noise assessments for offshore wind farms. A suggestion for an offshore measurement method is described and a survey of models for noise propagation offshore has been made. (au)

  7. The aerodynamics of wind turbines

    DEFF Research Database (Denmark)

    Sørensen, Jens Nørkær; Mikkelsen, Robert Flemming; Troldborg, Niels

    2013-01-01

    In the paper we present state-of-the-art of research in wind turbine aerodynamics. We start be giving a brief historical review and a survey over aerodynamic research in wind energy. Next, we focus on some recent research results obtained by our wind energy group at Department of Mechanical...... Engineering at DTU. In particular, we show some new results on the classical problem of the ideal rotor and present a series of new results from an on-going research project dealing with the modelling and simulation of turbulent flow structures in the wake behind wind turbines....

  8. Extreme Response for Wind Turbines

    DEFF Research Database (Denmark)

    Toft, Henrik Stensgaard; Sørensen, John Dalsgaard

    2009-01-01

    The characteristic load on wind turbines during operation are among others dependent on the mean wind speed, the turbulence intensity and type and settings of the control system. The characteristic load during operation is normally estimated by statistical extrapolation of a limited number...... of simulated 10min time series of the response according to the wind turbine standard IEC 61400-1. However, this method assumes that the individual 10min time series and the extracted peaks from the time series are independent. In the present paper is this assumption investigated based on field measurements...

  9. Deformation behaviour of turbine foundations

    International Nuclear Information System (INIS)

    Koch, W.; Klitzing, R.; Pietzonka, R.; Wehr, J.

    1979-01-01

    The effects of foundation deformation on alignment in turbine generator sets have gained significance with the transition to modern units at the limit of design possibilities. It is therefore necessary to obtain clarification about the remaining operational variations of turbine foundations. Static measurement programmes, which cover both deformation processes as well as individual conditions of deformation are described in the paper. In order to explain the deformations measured structural engineering model calculations are being undertaken which indicate the effect of limiting factors. (orig.) [de

  10. Failure analysis of turbine blades

    International Nuclear Information System (INIS)

    Iorio, A.F.; Crespi, J.C.

    1989-01-01

    Two 20 MW gas turbines suffered damage in blades belonging to the 2nd. stage of the turbine after 24,000 hours of duty. From research it arises that the fuel used is not quite adequate to guarantee the blade's operating life due to the excess of SO 3 , C and Na existing in combustion gases which cause pitting to the former. Later, the corrosion phenomenon is presented under tension produced by working stress enhanced by pitting where Pb is its main agent. A change of fuel is recommended thus considering the blades will reach the operational life they were designed for. (Author) [es

  11. Aeroderivative gas turbines for cogeneration

    International Nuclear Information System (INIS)

    Horner, M.W.; Thames, J.M.

    1988-01-01

    Aircraft jet engine derivative gas turbines have gained acceptance for cogeneration applications through impressive advances in technology and especially in maintainability and reliability. The best advantages of heavy industrial turbines and of reliable commercial airline jet engines have been successfully joined to meet the requirements for industrial cogeneration service. The next generation is under development and offers improved thermal efficiencies, alternate fuel capabilities, low environmental emissions, flexibility of operation and improved competitive system economics. This paper summarizes the current aero-derivative engine features and advantages with various systems, and discusses advanced features under consideration at this time

  12. Reliability Modeling of Wind Turbines

    DEFF Research Database (Denmark)

    Kostandyan, Erik

    Cost reductions for offshore wind turbines are a substantial requirement in order to make offshore wind energy more competitive compared to other energy supply methods. During the 20 – 25 years of wind turbines useful life, Operation & Maintenance costs are typically estimated to be a quarter...... and uncertainties are quantified. Further, estimation of annual failure probability for structural components taking into account possible faults in electrical or mechanical systems is considered. For a representative structural failure mode, a probabilistic model is developed that incorporates grid loss failures...

  13. Dynamic solar-powered multi-stage direct contact membrane distillation system: Concept design, modeling and simulation

    KAUST Repository

    Lee, Jung Gil; Kim, Woo-Seung; Choi, June-Seok; Ghaffour, NorEddine; Kim, Young-Deuk

    2017-01-01

    This paper presents a theoretical analysis of the monthly average daily and hourly performances of a solar-powered multi-stage direct contact membrane distillation (SMDCMD) system with an energy recovery scheme and dynamic operating system. Mid

  14. Across the dam for turbines; Over dammen etter turbiner

    Energy Technology Data Exchange (ETDEWEB)

    Bakken, Marte

    2010-07-01

    Raanaasfoss is one step closer to upgrading. Model testing in the U.S. have now shown that the upgrade can provide approximately 20 G Wh higher production per year. The power plant is 90 years old and is to be upgraded by six new turbines and generators. Buildings and dams are to remain. (AG)

  15. Coarse Grid Modeling of Turbine Film Cooling Flows Using Volumetric Source Terms

    Science.gov (United States)

    Heidmann, James D.; Hunter, Scott D.

    2001-01-01

    The recent trend in numerical modeling of turbine film cooling flows has been toward higher fidelity grids and more complex geometries. This trend has been enabled by the rapid increase in computing power available to researchers. However, the turbine design community requires fast turnaround time in its design computations, rendering these comprehensive simulations ineffective in the design cycle. The present study describes a methodology for implementing a volumetric source term distribution in a coarse grid calculation that can model the small-scale and three-dimensional effects present in turbine film cooling flows. This model could be implemented in turbine design codes or in multistage turbomachinery codes such as APNASA, where the computational grid size may be larger than the film hole size. Detailed computations of a single row of 35 deg round holes on a flat plate have been obtained for blowing ratios of 0.5, 0.8, and 1.0, and density ratios of 1.0 and 2.0 using a multiblock grid system to resolve the flows on both sides of the plate as well as inside the hole itself. These detailed flow fields were spatially averaged to generate a field of volumetric source terms for each conservative flow variable. Solutions were also obtained using three coarse grids having streamwise and spanwise grid spacings of 3d, 1d, and d/3. These coarse grid solutions used the integrated hole exit mass, momentum, energy, and turbulence quantities from the detailed solutions as volumetric source terms. It is shown that a uniform source term addition over a distance from the wall on the order of the hole diameter is able to predict adiabatic film effectiveness better than a near-wall source term model, while strictly enforcing correct values of integrated boundary layer quantities.

  16. Multi-stage crypto ransomware attacks: A new emerging cyber threat to critical infrastructure and industrial control systems

    OpenAIRE

    Aaron Zimba; Zhaoshun Wang; Hongsong Chen

    2018-01-01

    The inevitable integration of critical infrastructure to public networks has exposed the underlying industrial control systems to various attack vectors. In this paper, we model multi-stage crypto ransomware attacks, which are today an emerging cyber threat to critical infrastructure. We evaluate our modeling approach using multi-stage attacks by the infamous WannaCry ransomware. The static malware analysis results uncover the techniques employed by the ransomware to discover vulnerable nodes...

  17. Immunogenic multistage recombinant protein vaccine confers partial protection against experimental toxoplasmosis mimicking natural infection in murine model

    Directory of Open Access Journals (Sweden)

    Yaprak Gedik

    2016-01-01

    To generate a protective vaccine against toxoplasmosis, multistage vaccines and usage of challenging models mimicking natural route of infection are critical cornerstones. In this study, we generated a BAG1 and GRA1 multistage vaccine that induced strong immune response in which the protection was not at anticipated level. In addition, the murine model was orally challenged with tissue cysts to mimic natural route of infection.

  18. Design of Wind Turbine Vibration Monitoring System

    Directory of Open Access Journals (Sweden)

    Shoubin Wang

    2013-04-01

    Full Text Available In order to ensure safety of wind turbine operation and to reduce the occurrence of faults as well as to improve the reliability of wind turbine operation, a vibration monitoring for wind turbine is developed. In this paper, it analyses the enlargement of all the parts of the structure and the working mechanism, the research method of wind turbine operation vibration is introduced, with the focus being the use of the sensor principle. Finally the hardware design and software of this system is introduced and the main function of this system is described, which realizes condition monitoring of the work state of wind turbines.

  19. Aeroelastic instability problems for wind turbines

    DEFF Research Database (Denmark)

    Hansen, Morten Hartvig

    2007-01-01

    This paper deals with the aeroelostic instabilities that have occurred and may still occur for modem commercial wind turbines: stall-induced vibrations for stall-turbines, and classical flutter for pitch-regulated turbines. A review of previous works is combined with derivations of analytical...... stiffness and chordwise position of the center of gravity along the blades are the main parameters for flutter. These instability characteristics are exemplified by aeroelastic stability analyses of different wind turbines. The review of each aeroelastic instability ends with a list of current research...... issues that represent unsolved aeroelostic instability problems for wind turbines. Copyright (c) 2007 John Wiley & Sons, Ltd....

  20. Coordinated Control of Cross-Flow Turbines

    Science.gov (United States)

    Strom, Benjamin; Brunton, Steven; Polagye, Brian

    2016-11-01

    Cross-flow turbines, also known as vertical-axis turbines, have several advantages over axial-flow turbines for a number of applications including urban wind power, high-density arrays, and marine or fluvial currents. By controlling the angular velocity applied to the turbine as a function of angular blade position, we have demonstrated a 79 percent increase in cross-flow turbine efficiency over constant-velocity control. This strategy uses the downhill simplex method to optimize control parameter profiles during operation of a model turbine in a recirculating water flume. This optimization method is extended to a set of two turbines, where the blade motions and position of the downstream turbine are optimized to beneficially interact with the coherent structures in the wake of the upstream turbine. This control scheme has the potential to enable high-density arrays of cross-flow turbines to operate at cost-effective efficiency. Turbine wake and force measurements are analyzed for insight into the effect of a coordinated control strategy.

  1. Turbines for nuclear power plants. 2.ed.

    International Nuclear Information System (INIS)

    Troyanovskij, B.M.

    1978-01-01

    In the second edition of the book considered are practically all the main problems of calculation and operation of turbines and turbine installations of nuclear power plants. As compared to the first edition, essentially addes is the reproduction of the problem on combined generation of heat and electric energy. Also represented is detailed material on methods of preliminary evaluation of turbine effectiveness. Considered are peculiarities of turbine operation on wet steam and the basis of their thermal calculation. Much attention is payed to the problem of wet stream current in the turbine elements and wetness effect on their characteristics. Problems of wetness separation and moving blade erosion as well as other turbine elements are extracted in a special section. Given are structural schemes of different methods of innerchannel and periphery wet removal as well as experimental materials on their effectiveness. Given are descriptions and critical analysis of a great number of typical constructions of nuclear power plant steam turbines, produced by native plants as well as by the main foreign firms. Considered also are constructions of outside separators and steam superheaters. Separately given is the problem of rotation frequency choise of nuclear power plant wet steam turbines. Represented are materials on turbine installation tests, considered are the problems of turbine starting and manoeuvrability, analyzed are their typical jailures and damages. One of the sections of the book is devoted to gas turbine installations of nuclear power plants. Different material on this theme scattered before in various sources is summarized in the book

  2. New guidelines for wind turbine gearboxes

    Energy Technology Data Exchange (ETDEWEB)

    McNiff, B. [McNiff Light Industry, Blue Hill, ME (United States); Errichello, R. [GEARTECH, Townsend, MT (United States)

    1997-12-31

    The American Gear Manufacturers Association in cooperation with the American Wind Energy Association will soon be publishing AGMA/AWEA 921-A97 {open_quotes}Recommended Practices for Design and Specification of Gearboxes for Wind Turbine Generator Systems.{close_quotes} Much has been learned about the unique operation and loading of gearboxes in wind turbine applications since the burgeoning of the modern wind turbine industry in the early 1980`s. AGMA/AWEA 921-A97 documents this experience in a manner that provides valuable information to assist gear manufacturers and wind turbine designers, operators, and manufacturers in developing reliable wind turbine gearboxes. The document provides information on procurement specification development, wind turbine architecture, environmental considerations, and gearbox load determination, as well as the design, manufacturing, quality assurance, lubrication, operation and maintenance of wind turbine gearboxes. This paper presents the salient parts of the practices recommended in AGMA/AWEA 921-A97.

  3. Wind turbines, is it just wind?

    International Nuclear Information System (INIS)

    Boiteux, M.

    2012-01-01

    The author first outlines that wind energy is not only random, but almost absent in extreme situations when it would be needed (for example and notably, very cold weather without wind). He suggests the association of a gas turbine to each wind turbine, so that the gas turbine will replace non operating wind turbines. He notices that wind turbines are not proximity energy as they were said to be, and that profitability in fact requires tens of grouped giant wind turbines. He also outlines the high cost of construction of grids for the connection of these wind turbines. Thus, he states that wind energy is far from being profitable in the present conditions of electricity tariffs in France

  4. Dynamic modeling and simulation of wind turbines

    International Nuclear Information System (INIS)

    Ghafari Seadat, M.H.; Kheradmand Keysami, M.; Lari, H.R.

    2002-01-01

    Using wind energy for generating electricity in wind turbines is a good way for using renewable energies. It can also help to protect the environment. The main objective of this paper is dynamic modeling by energy method and simulation of a wind turbine aided by computer. In this paper, the equations of motion are extracted for simulating the system of wind turbine and then the behavior of the system become obvious by solving the equations. The turbine is considered with three blade rotor in wind direction, induced generator that is connected to the network and constant revolution for simulation of wind turbine. Every part of the wind turbine should be simulated for simulation of wind turbine. The main parts are blades, gearbox, shafts and generator

  5. Development of high temperature turbine

    Energy Technology Data Exchange (ETDEWEB)

    Takahara, Kitao; Nouse, Hiroyuki; Yoshida, Toyoaki; Minoda, Mitsuhiro; Matsusue, Katsutoshi; Yanagi, Ryoji

    1988-07-01

    For the contribution to the development of FJR710, high by-pass ratio turbofan engine, with the study for many years of the development of high efficiency turbine for the jet engine, the first technical prize from the Energy Resource Research Committee was awarded in April, 1988. This report introduced its technical contents. In order to improve the thermal efficiency and enlarge the output, it is very effective to raise the gas temperature at the inlet of gas turbine. For its purpose, by cooling the nozzle and moving blades and having those blades operate at lower temperature than that of the working limitation, they realized, for the first time in Japan, the technique of cooling turbine to heighten the operational gas temperature. By that technique, it was enabled to raise the gas temperature at the inlet of turbine, to 1,350/sup 0/C from 850/sup 0/C. This report explain many important points of study covering the basic test, visualizing flow experiment, material discussion and structural design in the process of development. (9 figs)

  6. Hywind floating wind turbine project

    Energy Technology Data Exchange (ETDEWEB)

    Crome, Tim

    2010-07-01

    The Hywind floating wind turbine concept was developed by StatoilHydro. Technip was awarded the contract for engineering, fabrication and installation of a demonstration unit in May 2008 and the completed wind turbine was installed mid June 2009 at the west coast of Norway on 220 m water depth. The demonstration unit will generate 2,3 MW and is equipped with instrumentation for monitoring mooring forces, strains and motions. The fabrication of the SPAR type steel substructure was performed at Technip Offshore Finland facilities in Pori and was towed horizontally from Finland to Norway, where it was upended to a vertical position by water filling. The completed floating wind turbine was towed vertically to the final location west of Karmoey and connected to the pre-installed three legged anchor system using an Anchor Handling Tug type vessel. The wind turbine test period is scheduled to start in September 2009. Statoil will monitor the performance of the system for two years before decision will be taken for further development. The paper will present the main challenges and lessons learned through design, fabrication and installation of this first of its kind structure. Main emphasis will be on the special challenges experienced for this floating, catenary moored, slender unit which is highly exposed for wind induced forces in addition to current and waves in hostile North Sea environments. (Author)

  7. Rotor and wind turbine formalism

    DEFF Research Database (Denmark)

    Branlard, Emmanuel Simon Pierre

    2017-01-01

    The main conventions used in this book for the study of rotors are introduced in this chapter. The main assumptions and notations are provided. The formalism specific to wind turbines is presented. The forces, moments, velocities and dimensionless coefficients used in the study of rotors...

  8. ADVANCED GAS TURBINE SYSTEMS RESEARCH

    Energy Technology Data Exchange (ETDEWEB)

    Unknown

    2002-04-01

    The activities of the Advanced Gas Turbine Systems Research (AGTSR) program for this reporting period are described in this quarterly report. The report is divided into discussions of Membership, Administration, Technology Transfer (Workshop/Education), Research and Miscellaneous Related Activity. Items worthy of note are presented in extended bullet format following the appropriate heading.

  9. ADVANCED GAS TURBINE SYSTEMS RESEARCH

    Energy Technology Data Exchange (ETDEWEB)

    Unknown

    2002-02-01

    The activities of the Advanced Gas Turbine Systems Research (AGTSR) program for this reporting period are described in this quarterly report. The report is divided into discussions of Membership, Administration, Technology Transfer (Workshop/Education), Research and Miscellaneous Related Activity. Items worthy of note are presented in extended bullet format following the appropriate heading.

  10. Large nuclear steam turbine plants

    International Nuclear Information System (INIS)

    Urushidani, Haruo; Moriya, Shin-ichi; Tsuji, Kunio; Fujita, Isao; Ebata, Sakae; Nagai, Yoji.

    1986-01-01

    The technical development of the large capacity steam turbines for ABWR plants was partially completed, and that in progress is expected to be completed soon. In this report, the outline of those new technologies is described. As the technologies for increasing the capacity and heightening the efficiency, 52 in long blades and moisture separating heaters are explained. Besides, in the large bore butterfly valves developed for making the layout compact, the effect of thermal efficiency rise due to the reduction of pressure loss can be expected. As the new technology on the system side, the simplification of the turbine system and the effect of heightening the thermal efficiency by high pressure and low pressure drain pumping-up method based on the recent improvement of feed water quality are discussed. As for nuclear steam turbines, the actual records of performance of 1100 MW class, the largest output at present, have been obtained, and as a next large capacity machine, the development of a steam turbine of 1300 MWe class for an ABWR plant is in progress. It can be expected that by the introduction of those new technologies, the plants having high economical efficiency are realized. (Kako, I.)

  11. Turbine lubrication fluid varnish mitigation

    Energy Technology Data Exchange (ETDEWEB)

    Farooq, Khalid [Pall Corporation, Port Washington, NY (United States)

    2010-04-15

    Varnish deposits on internal surfaces in turbine lube systems result in a number of adverse operational issues, especially the restriction and sticking of the moving parts of servo- or directional control valves, resulting in their malfunction. The lubrication fluid has limited solvency for the varnish-forming material, hence a typical turbine will have the majority of this material as deposits and a relatively small portion as suspension in the fluid phase, in quasi-equilibrium with the deposits. The lube system needs to be cleaned by removing the suspended varnish-forming material from the fluid phase, which allows the deposits to re-entrain into the fluid phase, until the majority of the transferable deposits are removed and the fluid carries no significant amount of the material to have any adverse effect. The methods used for the removal of varnish from turbine lube systems include chemical cleaning/flushing, electrostatic charge induced agglomeration/retention, and the adsorption of the varnish suspended in the oil on an adsorbent medium. The paper discusses an absorption-based removal method that utilizes a fibrous medium that has pronounced affinity for the removal and retention of the varnish-forming material from the fluid as well as the deposits from surfaces that are in quasi-equilibrium with the varnish precursors in the fluid. The filtration medium is a composite, made with cellulose bonded by specially formulated, temperature-cured resins. The absorptive medium exhibits high structural and chemical integrity and has been thoroughly tested on operating turbines, showing reduction in varnish levels from the critical range to below normal range in a relatively short time. The experience with the utilization of the absorptive medium in laboratory tests and in two operating turbines is presented. (orig.)

  12. Computational Study on the Effect of Shroud Shape on the Efficiency of the Gas Turbine Stage

    Science.gov (United States)

    Afanas'ev, I. V.; Granovskii, A. V.

    2018-03-01

    The last stages of powerful power gas turbines play an important role in the development of power and efficiency of the whole unit as well as in the distribution of the flow parameters behind the last stage, which determines the efficient operation of the exhaust diffusers. Therefore, much attention is paid to improving the efficiency of the last stages of gas turbines as well as the distribution of flow parameters. Since the long blades of the last stages of multistage high-power gas turbines could fall into the resonance frequency range in the course of operation, which results in the destruction of the blades, damping wires or damping bolts are used for turning out of resonance frequencies. However, these damping elements cause additional energy losses leading to a reduction in the efficiency of the stage. To minimize these losses, dampening shrouds are used instead of wires and bolts at the periphery of the working blades. However, because of the strength problems, designers have to use, instead of the most efficient full shrouds, partial shrouds that do not provide for significantly reducing the losses in the tip clearance between the blade and the turbine housing. In this paper, a computational study is performed concerning an effect that the design of the shroud of the turbine-working blade exerted on the flow structure in the vicinity of the shroud and on the efficiency of the stage as a whole. The analysis of the flow structure has shown that a significant part of the losses under using the shrouds is associated with the formation of vortex zones in the cavities on the turbine housing before the shrouds, between the ribs of the shrouds, and in the cavities at the outlet behind the shrouds. All the investigated variants of a partial shrouding are inferior in efficiency to the stages with shrouds that completely cover the tip section of the working blade. The stage with a unshrouded working blade was most efficient at the values of the relative tip clearance

  13. Interactive flow field around two Savonius turbines

    Energy Technology Data Exchange (ETDEWEB)

    Shigetomi, Akinari; Murai, Yuichi; Tasaka, Yuji; Takeda, Yasushi [Laboratory for Flow Control, Division of Energy and Environmental System, Faculty of Engineering, Hokkaido University, N13W8, Sapporo 060-8628 (Japan)

    2011-02-15

    The use of a Savonius type of vertical axis wind turbine is expanding in urban environments as a result of its ability to withstand turbulence as well as its relatively quiet operation. In the past, single turbine performance has been investigated primarily for determining the optimum blade configuration. In contrast, combining multiple Savonius turbines in the horizontal plane produces extra power in particular configurations. This results from the interaction between the two flow fields around individual turbines. To understand quantitatively the interaction mechanism, we measured the flow field around two Savonius turbines in close configurations using particle image velocimetry. The phase-averaged flow fields with respect to the rotation angle of the turbines revealed two types of power-improvement interactions. One comes from the Magnus effect that bends the main stream behind the turbine to provide additional rotation of the downstream turbine. The other is obtained from the periodic coupling of local flow between the two turbines, which is associated with vortex shedding and cyclic pressure fluctuations. Use of this knowledge will assist the design of packaged installations of multiple Savonius turbines. (author)

  14. Airfoil for a turbine of a gas turbine engine

    Science.gov (United States)

    Liang, George

    2010-12-21

    An airfoil for a turbine of a gas turbine engine is provided. The airfoil comprises a main body comprising a wall structure defining an inner cavity adapted to receive a cooling air. The wall structure includes a first diffusion region and at least one first metering opening extending from the inner cavity to the first diffusion region. The wall structure further comprises at least one cooling circuit comprising a second diffusion region and at least one second metering opening extending from the first diffusion region to the second diffusion region. The at least one cooling circuit may further comprise at least one third metering opening, at least one third diffusion region and a fourth diffusion region.

  15. Hydro turbine rehab benefits from modeling

    International Nuclear Information System (INIS)

    Froehlich, D.R.; Veatch, J.A.

    1991-01-01

    The turbine aging process, while seemingly imperceptible, inevitably results in reduced turbine efficiency and capacity. The primary causes of these reductions are runner hydraulic profile changes during weld repairs, surface finish deterioration from cavitation, and runner seal clearance increases due to wear. Many aging turbines require more frequent repairs due to runner cavitation, and wicket gate mechanism, shaft seal, and guide bearing wear. In many instances turbine component repair can be performed in-place. On older units, runner seals, wicket gate bearings, and wicket gate end seals can be repaired only when the turbine is disassembled. Since the significant cost to disassemble and overhaul units must be offset by future maintenance savings and generation increases, turbine rehabilitation is often postponed as owners consider other alternatives. Rehabilitation is a general term used to describe a wide range of turbine reconditioning and design alternatives. Turbine rehabilitation can include a major overhaul of components, runner replacement, and component modifications. Deteriorated runners can be replaced with either a new identical runner or a new modern design having increased efficiency and capacity. The comparative turbine performance of an original, existing, and a modern runner design are shown in this paper. Component overhauls can extend turbine life and restore original efficiency and capacity to existing units. However, the overhaul of existing components cannot increase plant capacity and generation above the as-new values. As a result, owners of aging plants are considering the benefits of replacing existing turbines with modern, more efficient, higher capacity turbines, or expanding the sites. Where expansion is not feasible, hydroelectric power plant owners are finding that turbine rehabilitation is the most cost-effective method to increase plant value and life

  16. Insight analysis of biplane Wells turbine performance

    International Nuclear Information System (INIS)

    Shaaban, S.

    2012-01-01

    Highlights: ► Downstream rotor reduces overall turbine efficiency during normal operation. ► Recirculation behind downstream rotor significantly reduces the torque delivered by the turbine. ► Upstream rotor significantly affects downstream rotor performance even at high gap to chord ratios. ► Downstream rotor produces only 10–30% of the turbine power despite its feasible exergy level. ► The downstream rotor significantly delays turbine start up. - Abstract: Wells turbines are very promising in converting wave energy. Improving the design and performance of Wells turbines requires deep understanding of the energy conversion process and losses mechanisms of these energy convertors. The performance of a biplane Wells turbine having 45° stagger angle between rotors is numerically investigated. The turbine performance is simulated by solving the steady 3D incompressible Reynolds Averaged Navier–Stocks equation (RANS). The present numerical investigation shows that the upstream rotor significantly affects the downstream rotor performance even at high gap-to-chord ratio (G/c = 1.4). The contribution of the downstream rotor in the overall biplane Wells turbine performance is limited. The downstream rotor torque represents 10–30% of the total turbine torque and the upstream rotor efficiency is 1.5–5 times the downstream rotor efficiency at normal operating conditions. Exergy analysis shows that the downstream rotor is the main component that reduces the turbine second law efficiency. The blade exergy increases from hub to tip and decreases from leading edge to trailing edge. Therefore, 3D blade profile optimization is essential for substantial improvement of the energy conversion process. Improving the design of the inter-rotors zone can significantly improve biplane Wells turbine performance. Future biplane Wells turbine designs should focus essentially on improving the downstream rotor performance.

  17. Bimetallic Blisks with Shrouded Turbine Blades for Gas Turbine Engines

    Directory of Open Access Journals (Sweden)

    L. A. Magerramova

    2015-01-01

    Full Text Available The paper discusses prospects of using blisks with shrouded blades. Increasing an engine life and efficiency as well as mass reduction can also be achieved by increasing blade numbers and decreasing disk diameter. But design engineers are faced with the problem of blade placement because of the disk size and root dimensions.The problem of increasing life and cyclic durability, vibration strength, and lightweight design of the turbine gas turbine wheels, can be solved by an elimination of blade - disk locks.The technology of manufacturing one-piece blisks by connecting the blades with the disc part using hot isostatic pressing was developed. This technology allows us to use blades with shrouds. It is necessary to increase efficiency and to improve high cycle fatigue performance of rotor blades.One of the pressing problems is to ensure the necessary position of shrouds in relation to each other in the manufacturing process as well as in the service. Numerical studies of the influence of the shroud mounting position on blade strength during operation allowed us to develop a methodology of choosing a shroud mounting position.Based on the two turbine wheels (LPT and HPT calculations advantages of blisk design with respect to the lock-based design were shown. Application of bimetallic blisks with shrouded blades resulted in a lifespan increase and weight reduction.In addition, other advantages of blisk design are as follows: possible reduction in the number of parts, elimination of leaks and fretting that take place in the blade - disk locks, exception of expensive broaching operations and disk alloy saving. The shortcoming is elimination of damping in root connection. In addition, there are no widely used repair methods.Despite these disadvantages the usage of bimetallic turbine blisks with shrouded blades is very promising.

  18. Direct Numerical Simulation of Turbulent Multi-Stage Autoignition Relevant to Engine Conditions

    Science.gov (United States)

    Chen, Jacqueline

    2017-11-01

    Due to the unrivaled energy density of liquid hydrocarbon fuels combustion will continue to provide over 80% of the world's energy for at least the next fifty years. Hence, combustion needs to be understood and controlled to optimize combustion systems for efficiency to prevent further climate change, to reduce emissions and to ensure U.S. energy security. In this talk I will discuss recent progress in direct numerical simulations of turbulent combustion focused on providing fundamental insights into key `turbulence-chemistry' interactions that underpin the development of next generation fuel efficient, fuel flexible engines for transportation and power generation. Petascale direct numerical simulation (DNS) of multi-stage mixed-mode turbulent combustion in canonical configurations have elucidated key physics that govern autoignition and flame stabilization in engines and provide benchmark data for combustion model development under the conditions of advanced engines which operate near combustion limits to maximize efficiency and minimize emissions. Mixed-mode combustion refers to premixed or partially-premixed flames propagating into stratified autoignitive mixtures. Multi-stage ignition refers to hydrocarbon fuels with negative temperature coefficient behavior that undergo sequential low- and high-temperature autoignition. Key issues that will be discussed include: 1) the role of mixing in shear driven turbulence on the dynamics of multi-stage autoignition and cool flame propagation in diesel environments, 2) the role of thermal and composition stratification on the evolution of the balance of mixed combustion modes - flame propagation versus spontaneous ignition - which determines the overall combustion rate in autoignition processes, and 3) the role of cool flames on lifted flame stabilization. Finally prospects for DNS of turbulent combustion at the exascale will be discussed in the context of anticipated heterogeneous machine architectures. sponsored by DOE

  19. Final turbine and test facility design report Alden/NREC fish friendly turbine

    Energy Technology Data Exchange (ETDEWEB)

    Cook, Thomas C. [Alden Research Lab., Holden, MA (United States); Cain, Stuart A. [Alden Research Lab., Holden, MA (United States); Fetfatsidis, Paul [Alden Research Lab., Holden, MA (United States); Hecker, George E. [Alden Research Lab., Holden, MA (United States); Stacy, Philip S. [Alden Research Lab., Holden, MA (United States)

    2000-09-01

    The final report provides an overview of the Alden/NREC Fish Friendly turbine design phase, turbine test plan, preliminary test results, costs, schedule, and a hypothetical application at a real world project.

  20. Rapid Growth of Large Single-Crystalline Graphene via Second Passivation and Multistage Carbon Supply.

    Science.gov (United States)

    Lin, Li; Sun, Luzhao; Zhang, Jincan; Sun, Jingyu; Koh, Ai Leen; Peng, Hailin; Liu, Zhongfan

    2016-06-01

    A second passivation and a multistage carbon-source supply (CSS) allow a 50-fold enhancement of the growth rate of large single-crystalline graphene with a record growth rate of 101 μm min(-1) , almost 10 times higher than for pure copper. To this end the CSS is tailored at separate stages of graphene growth on copper foil, combined with an effective suppression of new spontaneous nucleation via second passivation. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Enhanced Multistage Homotopy Perturbation Method: Approximate Solutions of Nonlinear Dynamic Systems

    Directory of Open Access Journals (Sweden)

    Daniel Olvera

    2014-01-01

    Full Text Available We introduce a new approach called the enhanced multistage homotopy perturbation method (EMHPM that is based on the homotopy perturbation method (HPM and the usage of time subintervals to find the approximate solution of differential equations with strong nonlinearities. We also study the convergence of our proposed EMHPM approach based on the value of the control parameter h by following the homotopy analysis method (HAM. At the end of the paper, we compare the derived EMHPM approximate solutions of some nonlinear physical systems with their corresponding numerical integration solutions obtained by using the classical fourth order Runge-Kutta method via the amplitude-time response curves.

  2. The multistage homotopy-perturbation method: A powerful scheme for handling the Lorenz system

    International Nuclear Information System (INIS)

    Chowdhury, M.S.H.; Hashim, I.; Momani, S.

    2009-01-01

    In this paper, a new reliable algorithm based on an adaptation of the standard homotopy-perturbation method (HPM) is presented. The HPM is treated as an algorithm in a sequence of intervals (i.e. time step) for finding accurate approximate solutions to the famous Lorenz system. Numerical comparisons between the multistage homotopy-perturbation method (MHPM) and the classical fourth-order Runge-Kutta (RK4) method reveal that the new technique is a promising tool for the nonlinear systems of ODEs.

  3. Modeling and simulation of a multistage-contactor for solvent extraction

    International Nuclear Information System (INIS)

    Oh, W.J.; Kim, C.; Lee, T.H.

    1977-01-01

    The hydrodynamic characteristics of Multistage Mixer-Settlers were studied by establishing a mathematical model based on the assumptions of complete mixing in the mixer and plug flow with CSTR recirculation in the settler. The model parameters were determined by the moment and time lag matching and experiments were carried out with a water-kerosene system by obtaining residence time distributions for both phases using impulse response technique. The suggested model well predicated the experimental results within the experimental error range, while the other existing models were found to be too idealized to depict the dynamic characteristics of this equipment. (author)

  4. A theoretical analysis of price elasticity of energy demand in multistage energy conversion systems

    International Nuclear Information System (INIS)

    Lowe, R.

    2003-01-01

    The objective of this paper is an analytical exploration of the problem of price elasticity of energy demand in multi-stage energy conversion systems. The paper describes in some detail an analytical model of energy demand in such systems. Under a clearly stated set of assumptions, the model makes it possible to explore both the impacts of the number of sub-systems, and of varying sub-system elasticities on overall system elasticity. The analysis suggests that overall price elasticity of energy demand for such systems will tend asymptotically to unity as the number of sub-systems increases. (author)

  5. A theoretical analysis of price elasticity of energy demand in multi-stage energy conversion systems

    International Nuclear Information System (INIS)

    Lowe, Robert

    2003-01-01

    The objective of this paper is an analytical exploration of the problem of price elasticity of energy demand in multi-stage energy conversion systems. The paper describes in some detail an analytical model of energy demand in such systems. Under a clearly stated set of assumptions, the model makes it possible to explore both the impacts of the number of sub-systems, and of varying sub-system elasticities on overall system elasticity. The analysis suggests that overall price elasticity of energy demand for such systems will tend asymptotically to unity as the number of sub-systems increases

  6. Multi-Stage Adaptive Noise Cancellation Technique for Synthetic Hard-α Inclusion

    International Nuclear Information System (INIS)

    Kim, Jae Joon

    2003-01-01

    Adaptive noise cancellation techniques are ideally suitable for reducing spatially varying noise due to the grain structure of material in ultrasonic nondestructive evaluation. Grain noises have an un-correlation property, while flaw echoes are correlated. Thus, adaptive filtering algorithms use the correlation properties of signals to enhance the signal-to-noise ratio (SNR) of the output signal. In this paper, a multi-stage adaptive noise cancellation (MANC) method using adaptive least mean square error (LMSE) filter for enhancing flaw detection in ultrasonic signals is proposed

  7. Changes in Cartilage Biomarker Levels During a Transcontinental Multistage Footrace Over 4486 km.

    Science.gov (United States)

    Mündermann, Annegret; Klenk, Christopher; Billich, Christian; Nüesch, Corina; Pagenstert, Geert; Schmidt-Trucksäss, Arno; Schütz, Uwe

    2017-09-01

    Cartilage turnover and load-induced tissue changes are frequently assessed by quantifying concentrations of cartilage biomarkers in serum. To date, information on the effects of ultramarathon running on articular cartilage is scarce. Serum concentrations of cartilage oligomeric matrix protein (COMP), matrix metalloproteinase (MMP)-1, MMP-3, MMP-9, COL2-3/4C long mono (C2C), procollagen type II C-terminal propeptide (CPII), and C2C:CPII will increase throughout a multistage ultramarathon. Descriptive laboratory study. Blood samples were collected from 36 runners (4 female; mean age, 49.0 ± 10.7 years; mean body mass index, 23.1 ± 2.3 kg/m 2 [start] and 21.4 ± 1.9 kg/m 2 [finish]) before (t 0 ) and during (t 1 : 1002 km; t 2 : 2132 km; t 3 : 3234 km; t 4 : 4039 km) a 4486-km multistage ultramarathon. Serum COMP, MMP-1, MMP-3, MMP-9, C2C, and CPII levels were assessed using commercial enzyme-linked immunosorbent assays. Linear mixed models were used to detect significant changes in serum biomarker levels over time with the time-varying covariates of body weight, running speed, and daily running time. Serum concentrations of COMP, MMP-9, and MMP-3 changed significantly throughout the multistage ultramarathon. On average, concentrations increased during the first measurement interval (MI1: t 1 -t 0 ) by 22.5% for COMP (95% CI, 0.29-0.71 ng/mL), 22.3% for MMP-3 (95% CI, 0.24-15.37 ng/mL), and 95.6% for MMP-9 (95% CI, 81.7-414.5 ng/mL) and remained stable throughout MI2, MI3, and MI4. Serum concentrations of MMP-1, C2C, CPII, and C2C:CPII did not change significantly throughout the multistage ultramarathon. Changes in MMP-3 were statistically associated with changes in COMP throughout the ultramarathon race (MMP-3: Wald Z = 3.476, P = .001). Elevated COMP levels indicate increased COMP turnover in response to extreme running, and the association between load-induced changes in MMP-3 and changes in COMP suggests the possibility that MMP-3 may be involved in the

  8. A Predictive Model of Multi-Stage Production Planning for Fixed Time Orders

    Directory of Open Access Journals (Sweden)

    Kozłowski Edward

    2014-09-01

    Full Text Available The traditional production planning model based upon a deterministic approach is well described in the literature. Due to the uncertain nature of manufacturing processes, such model can however incorrectly represent actual situations on the shop floor. This study develops a mathematical modeling framework for generating production plans in a multistage manufacturing process. The devised model takes into account the stochastic model for predicting the occurrence of faulty products. The aim of the control model is to determine the number of products which should be manufactured in each planning period to minimize both manufacturing costs and potential financial penalties for failing to fulfill the order completely.

  9. Modeling of changes in particle size distribution of solids in multistage separation systems

    Directory of Open Access Journals (Sweden)

    Lagereva E.A.

    2016-09-01

    Full Text Available The presented method of calculation of the separation of solid particles from gas streams to multistage separation sys-tems, consisting of a number of sequentially installed separational devices of various design and principle of operation. It is based on a separate analysis of the sequential processes of capture and transmission of individual fractions of solid particles of a polydisperse structure. The technique provides information about changes in particle size distribution of solids with the passage of the gas flow in the treatment system and allows you to specifically select the effective combination of different types of separators.

  10. Turbine-99 unsteady simulations - Validation

    International Nuclear Information System (INIS)

    Cervantes, M J; Andersson, U; Loevgren, H M

    2010-01-01

    The Turbine-99 test case, a Kaplan draft tube model, aimed to determine the state of the art within draft tube simulation. Three workshops were organized on the matter in 1999, 2001 and 2005 where the geometry and experimental data were provided as boundary conditions to the participants. Since the last workshop, computational power and flow modelling have been developed and the available data completed with unsteady pressure measurements and phase resolved velocity measurements in the cone. Such new set of data together with the corresponding phase resolved velocity boundary conditions offer new possibilities to validate unsteady numerical simulations in Kaplan draft tube. The present work presents simulation of the Turbine-99 test case with time dependent angular resolved inlet velocity boundary conditions. Different grids and time steps are investigated. The results are compared to experimental time dependent pressure and velocity measurements.

  11. The VGOT Darrieus wind turbine

    Energy Technology Data Exchange (ETDEWEB)

    Ponta, F.L.; Otero, A.D.; Lago, L. [University of Buenos Aires (Argentina). College of Engineering

    2004-07-01

    We present the actual state of development of a non-conventional new vertical-axis wind turbine. The concepts introduced here involve the constructive aspects of variable-geometry oval-trajectory (VGOT) Darrieus wind turbines. The key feature of a VGOT machine is that each blade slides over rails mounted on a wagon instead of rotating around a central vertical axis. Each wagon contains its own electrical generation system coupled to the power-wheels and the electricity is collected by a classical third rail system. The VGOT concept allows increasing the area swept by the blades, and hence the power output of the installation, without the structural problems and the low rotational speed associated with a classical Darrieus rotor of large diameter. We also propose some engineering solutions for the VGOT design and present a brief economic analysis of the feasibility of the project. (author)

  12. Turbine-99 unsteady simulations - Validation

    Science.gov (United States)

    Cervantes, M. J.; Andersson, U.; Lövgren, H. M.

    2010-08-01

    The Turbine-99 test case, a Kaplan draft tube model, aimed to determine the state of the art within draft tube simulation. Three workshops were organized on the matter in 1999, 2001 and 2005 where the geometry and experimental data were provided as boundary conditions to the participants. Since the last workshop, computational power and flow modelling have been developed and the available data completed with unsteady pressure measurements and phase resolved velocity measurements in the cone. Such new set of data together with the corresponding phase resolved velocity boundary conditions offer new possibilities to validate unsteady numerical simulations in Kaplan draft tube. The present work presents simulation of the Turbine-99 test case with time dependent angular resolved inlet velocity boundary conditions. Different grids and time steps are investigated. The results are compared to experimental time dependent pressure and velocity measurements.

  13. Airfoil characteristics for wind turbines

    DEFF Research Database (Denmark)

    Bak, C.; Fuglsang, P.; Sørensen, Niels N.

    1999-01-01

    Airfoil characteristics for use in the Blade Element Momentum (BEM) method calculating the forces on Horizontal Axis Wind Turbines (HAWT) are derived by use of systematic methods. The investigation and derivation of the airfoil characteristics are basedon four different methods: 1) Inverse momentum...... theory, 2) Actuator disc theory, 3) Numerical optimisation and 4) Quasi-3D CFD computations. The two former methods are based on 3D CFD computations and wind tunnel measurements on a 41-m full-scale rotorwith LM 19.1 blades. The derived airfoil characteristics show that the lift coefficient in stall...... to a commonly used set of airfoil characteristics. The numerical optimisation is based on both the 3D CFDcomputations and measurements on a 41-m rotor with LM 19.1 and LM 19.0 blades, respectively. The method requires power and loads from a turbine and is promising since a set of lift and drag curves is derived...

  14. Ultimate loading of wind turbines

    DEFF Research Database (Denmark)

    Larsen, Gunner Chr.; Ronold, K.; Ejsing Jørgensen, Hans

    1999-01-01

    An extreme loading study has been conducted comprising a general wind climate analysis as well as a wind turbine reliability study. In the wind climate analysis, the distribution of the (horizontal) turbulence standard deviation, conditioned on the meanwind speed, has been approximated by fitting......, a design turbulence intensity for off-shore application is proposed which, in the IEC code framework, is applicable for extreme as well as for fatigue loaddetermination. In order to establish a rational method to analyse wind turbine components with respect to failure in ultimate loading, and in addition...... a three parameter Weibull distribution to the measured on-shore and off-shore data for wind speed variations. Specific recommendations on off-shore design turbulence intensities are lacking in the presentIEC-code. Based on the present analysis of the off-shore wind climate on two shallow water sites...

  15. Leiomyosarcoma of the inferior turbinate

    Directory of Open Access Journals (Sweden)

    Christopher W. Harper, Jr., MD

    2017-09-01

    Full Text Available We report a case of leiomyosarcoma of the inferior nasal turbinate. The patient, a 68-year-old Caucasian male, presented with 4–6 weeks of epistaxis that was resistant to nasal packing and septal cautery. Upon inspection in the operating room, a small mass was excised from the inferior turbinate. High-power H&E-stained microscopy demonstrated bundles of malignant smooth muscle cells, and immunohistochemical stains were strongly positive for desmin, smooth muscle actin and vimentin, while negative for pankeratin EA1/EA3 and CaM 5.2, suggesting leiomyosarcoma as the diagnosis. Clear margins were obtained at a second surgery. At the time of this writing it is 8 months since his last surgery and he has remained symptom free.

  16. Icing losses on wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Duncan, T.; Fotsing, I.; Pearson, S. [Garrad Hassan Canada Inc., Ottawa, ON (Canada)

    2010-07-01

    This PowerPoint presentation discussed some of the energy losses that can occur as a result of icing on wind turbines. Airfoil deterioration can occur in the presence of rime and glaze ice. Anemometers are also impacted by ice, and shut-downs can occur as a result of icing events. Availability deficits that occur during the winter months can lead to annual energy losses of 0.5 percent. The impact of icing events on total wind power energy production in Quebec is estimated at between 1.3 percent to 2.7 percent. Ice loss estimates are considered during the pre-construction phases of wind power projects. However, ice loss prediction methods are often inaccurate. Studies have demonstrated that preconstruction masts show a reasonable correlation with wind turbine icing, and that icing losses are site-specific. tabs., figs.

  17. Gas turbine vane platform element

    Science.gov (United States)

    Campbell, Christian X [Oviedo, FL; Schiavo, Anthony L [Oviedo, FL; Morrison, Jay A [Oviedo, FL

    2012-08-28

    A gas turbine CMC shroud plate (48A) with a vane-receiving opening (79) that matches a cross-section profile of a turbine vane airfoil (22). The shroud plate (48A) has first and second curved circumferential sides (73A, 74A) that generally follow the curves of respective first and second curved sides (81, 82) of the vane-receiving opening. Walls (75A, 76A, 77A, 78A, 80, 88) extend perpendicularly from the shroud plate forming a cross-bracing structure for the shroud plate. A vane (22) may be attached to the shroud plate by pins (83) or by hoop-tension rings (106) that clamp tabs (103) of the shroud plate against bosses (105) of the vane. A circular array (20) of shroud plates (48A) may be assembled to form a vane shroud ring in which adjacent shroud plates are separated by compressible ceramic seals (93).

  18. REGENERATIVE GAS TURBINES WITH DIVIDED EXPANSION

    DEFF Research Database (Denmark)

    Elmegaard, Brian; Qvale, Einar Bjørn

    2004-01-01

    Recuperated gas turbines are currently drawing an increased attention due to the recent commercialization of micro gas turbines with recuperation. This system may reach a high efficiency even for the small units of less than 100 kW. In order to improve the economics of the plants, ways to improve...... their efficiency are always of interest. Recently, two independent studies have proposed recuperated gas turbines to be configured with the turbine expansion divided, in order to obtain higher efficiency. The idea is to operate the system with a gas generator and a power turbine, and use the gas from the gas...... divided expansion can be advantageous under certain circumstances. But, in order for todays micro gas turbines to be competitive, the thermodynamic efficiencies will have to be rather high. This requires that all component efficiencies including the recuperator effectiveness will have to be high...

  19. Sound wave contours around wind turbine arrays

    International Nuclear Information System (INIS)

    Van Beek, A.; Van Blokland, G.J.

    1993-02-01

    Noise pollution is an important factor in selecting suitable sites for wind turbines in order to realize 1000 MW of wind power as planned by the Dutch government for the year 2000. Therefore an accurate assessment of wind turbine noise is important. The amount of noise pollution from a wind turbine depends on the wind conditions. An existing standard method to assess wind turbine noise is supplemented and adjusted. In the first part of the investigation the method was developed and applied for a solitary sound source. In the second part attention is paid to the use of the method for wind turbine arrays. It appears that the adjusted method results in a shift of the contours of the permitted noise level. In general the contours are 15-25% closer to the wind farm, which means that the minimal permitted distance between houses and wind turbine arrays can be reduced. 14 figs., 1 tab., 4 appendices, 7 refs

  20. RBI Optimization of Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Ramírez, José G. Rangel; Sørensen, John Dalsgaard

    2009-01-01

    methods for oil & gas installations, a framework for optimal inspection and maintenance planning of offshore wind turbines is presented. Special aspects for offshore wind turbines considered are the fatigue loading characteristics where usually the wind loading are dominating the wave loading, wake......Wind turbines for electricity production have increased significantly the last years both in production capability and size. This development is expected to continue also in the coming years. Offshore wind turbines with an electricity production of 5-10 MW are planned. Typically, the wind turbine...... support structure is a steel structure consisting of a tower and a monopile, tripod or jacket type foundation. This paper considers aspects of inspection and maintenance planning of fatigue prone details in jacket and tripod type of wind turbine support structures. Based on risk-based inspection planning...

  1. Optimal Structural Reliability of Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Tarp-Johansen, N.J.

    2005-01-01

    The main failure modes of modern large wind turbines are fatigue failure of wings, hub, shaft and main tower, local buckling of main tower, and failure of the foundation. This paper considers reliability-based optimal design of wind turbines. Compared to onshore wind turbines and building...... structures, humans spent little time in the vicinity of offshore wind turbines and the probability of human injury during storm conditions is small. Further environmental pollution will also in general be small in case of failure. One could therefore argue that the reliability level of offshore wind turbines...... can be lower than for onshore wind turbines and other civil engineering structures and can be assessed by reliability-based cost-optimization. Specifically this paper considers the main tower and foundation. Both fatigue and ultimate strength failure modes are included. Different formulations...

  2. On the Fatigue Analysis of Wind Turbines

    Energy Technology Data Exchange (ETDEWEB)

    Sutherland, Herbert J.

    1999-06-01

    Modern wind turbines are fatigue critical machines that are typically used to produce electrical power from the wind. Operational experiences with these large rotating machines indicated that their components (primarily blades and blade joints) were failing at unexpectedly high rates, which led the wind turbine community to develop fatigue analysis capabilities for wind turbines. Our ability to analyze the fatigue behavior of wind turbine components has matured to the point that the prediction of service lifetime is becoming an essential part of the design process. In this review paper, I summarize the technology and describe the ''best practices'' for the fatigue analysis of a wind turbine component. The paper focuses on U.S. technology, but cites European references that provide important insights into the fatigue analysis of wind turbines.

  3. Electrohydraulic system to control NPP turbines

    International Nuclear Information System (INIS)

    Kosyak, Yu.F.; Virchenko, M.A.; Rozhanskij, V.E.; Rokhlenko, V.Yu.; Gapunin, A.Ya.; Zhornitskaya, T.Ya.; Rasskazov, I.Eh.; Butsenko, V.N.; Brajnin, L.S.; Makarenko, N.I.

    1985-01-01

    Operation regimes of electrohydraulic regulation system (EHRS) of NPP turbines, designed to control the turbine in start-up and working conditions, have been decribed. In start-up regimes EHRS ensures the testing of control valves of the turbine, the turn of the turbine from zero to the nominal rotation frequency (automatic, semiautomatic and manual regulation), turbine acceleration to test safety automatic systems, gradual change in rotation frequency during generator synchronization with circuit. Under working conditions EHRS ensures the maintenance of frequency, power and vapour pressure before the turbine. A block diagram of EHRS is presented. Sensors and electronic part of EHRS are supplied with triple reservation, which ensures a high relaibility of the system

  4. Built Environment Wind Turbine Roadmap

    Energy Technology Data Exchange (ETDEWEB)

    Smith, J. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Forsyth, T. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Sinclair, K. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Oteri, F. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2012-11-01

    The market currently encourages BWT deployment before the technology is ready for full-scale commercialization. To address this issue, industry stakeholders convened a Rooftop and Built-Environment Wind Turbine Workshop on August 11 - 12, 2010, at the National Wind Technology Center, located at the U.S. Department of Energy’s National Renewable Energy Laboratory in Boulder, Colorado. This report summarizes the workshop.

  5. Secondary middle turbinate: case report

    Energy Technology Data Exchange (ETDEWEB)

    Aburjeli, Bruna de Oliveira Melim; Avila, Ana Flavia Assis de; Diniz, Renata Lopes Furletti Caldeira; Motta, Emilia Guerra Pinto Coelho; Ribeiro, Marcelo Almeida; Moreira, Wanderval, E-mail: bruninha86@hotmail.com [Radiology and Imaging Diagnosis, Hospital Mater Dei, Belo Horizonte, MG (Brazil)

    2012-11-15

    Secondary middle turbinate is an anatomical variant rarely observed in the nasal cavity, firstly described by Khanobthamchai et al. as a bone structure originating from the lateral nasal wall and covered by soft tissue. In most cases reported in the literature, this variant is bilateral, occurring without associated complications. In the present report, the authors describe the case of patient of their institution with such anatomical variation. (author)

  6. Gas Turbine Engine Behavioral Modeling

    OpenAIRE

    Meyer, Richard T; DeCarlo, Raymond A.; Pekarek, Steve; Doktorcik, Chris

    2014-01-01

    This paper develops and validates a power flow behavioral model of a gas tur- bine engine with a gas generator and free power turbine. “Simple” mathematical expressions to describe the engine’s power flow are derived from an understand- ing of basic thermodynamic and mechanical interactions taking place within the engine. The engine behavioral model presented is suitable for developing a supervisory level controller of an electrical power system that contains the en- gine connected to a gener...

  7. Acoustic Liners for Turbine Engines

    Science.gov (United States)

    Jones, Michael G (Inventor); Grady, Joseph E (Inventor); Kiser, James D. (Inventor); Miller, Christopher (Inventor); Heidmann, James D. (Inventor)

    2016-01-01

    An improved acoustic liner for turbine engines is disclosed. The acoustic liner may include a straight cell section including a plurality of cells with straight chambers. The acoustic liner may also include a bent cell section including one or more cells that are bent to extend chamber length without increasing the overall height of the acoustic liner by the entire chamber length. In some cases, holes are placed between cell chambers in addition to bending the cells, or instead of bending the cells.

  8. Airfoil characteristics for wind turbines

    OpenAIRE

    Bak, C.; Fuglsang, P.; Sørensen, Niels N.; Aagaard Madsen, Helge; Shen, W.Z.; Sørensen, Jens Nørkær

    1999-01-01

    Airfoil characteristics for use in the Blade Element Momentum (BEM) method calculating the forces on Horizontal Axis Wind Turbines (HAWT) are derived by use of systematic methods. The investigation and derivation of the airfoil characteristics are basedon four different methods: 1) Inverse momentum theory, 2) Actuator disc theory, 3) Numerical optimisation and 4) Quasi-3D CFD computations. The two former methods are based on 3D CFD computations and wind tunnel measurements on a 41-m full-scal...

  9. A new bladeless hydraulic turbine

    Czech Academy of Sciences Publication Activity Database

    Beran, V.; Sedláček, M.; Maršík, František

    2013-01-01

    Roč. 104, APR 2013 (2013), s. 978-983 ISSN 0306-2619 R&D Projects: GA ČR GAP201/10/0357 Institutional research plan: CEZ:AV0Z20760514 Institutional support: RVO:61388998 Keywords : rolling turbine * low head hydro power * stability of flow Subject RIV: BK - Fluid Dynamics Impact factor: 5.261, year: 2013 http://dx.doi.org/10.1016/j.apenergy.2012.12.016

  10. Secondary middle turbinate: case report

    International Nuclear Information System (INIS)

    Aburjeli, Bruna de Oliveira Melim; Avila, Ana Flavia Assis de; Diniz, Renata Lopes Furletti Caldeira; Motta, Emilia Guerra Pinto Coelho; Ribeiro, Marcelo Almeida; Moreira, Wanderval

    2012-01-01

    Secondary middle turbinate is an anatomical variant rarely observed in the nasal cavity, firstly described by Khanobthamchai et al. as a bone structure originating from the lateral nasal wall and covered by soft tissue. In most cases reported in the literature, this variant is bilateral, occurring without associated complications. In the present report, the authors describe the case of patient of their institution with such anatomical variation. (author)

  11. Hydrogen iodide processing section in a thermochemical water-splitting iodine-sulfur process using a multistage hydrogen iodide decomposer

    International Nuclear Information System (INIS)

    Ohashi, Hirofumi; Sakaba, Nariaki; Imai, Yoshiyuki; Kubo, Shinji; Sato, Hiroyuki; Tachibana, Yukio; Kunitomi, Kazuhiko; Kato, Ryoma

    2009-01-01

    A multistage hydrogen iodide (HI) decomposer (repetition of HI decomposition reaction and removal of product iodine by a HIx solution) in a thermochemical water-splitting iodine-sulfur process for hydrogen production using high-temperature heat from the high-temperature gas-cooled reactor was numerically evaluated, especially in terms of the flow rate of undecomposed HI and product iodine at the outlet of the decomposer, in order to reduce the total heat transfer area of heat exchangers for the recycle of undecomposed HI and to eliminate components for the separation. A suitable configuration of the multistage HI decomposer was countercurrent rather than concurrent, and the HIx solution from an electro-electro dialysis at a low temperature was a favorable feed condition for the multistage HI decomposer. The flow rate of undecomposed HI and product iodine at the outlet of the multistage HI decomposer was significantly lower than that of the conventional HI decomposer, because the conversion was increased, and HI and iodine were removed by the HIx solution. Based on this result, an alternative HI processing section using the multistage HI decomposer and eliminating some recuperators, coolers, and components for the separation was proposed and evaluated. The total heat transfer area of heat exchangers in the proposed HI processing section could be reduced to less than about 1/2 that in the conventional HI processing section. (author)

  12. Market for wind turbines in italy

    International Nuclear Information System (INIS)

    1997-01-01

    Wind power utilization in Italy has not been very popular until the privatization of the ENEL and introduction of subsidies for private electricity producers. The greatest interest is concentrated around large wind turbines. Therefore the Danish manufacturers with know-how within large wind turbines can establish themselves on the Italian market. Cooperation with one of the four local wind turbine manufacturers is advisable. (EG)

  13. Small Wind Research Turbine: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Corbus, D.; Meadors, M.

    2005-10-01

    The Small Wind Research Turbine (SWRT) project was initiated to provide reliable test data for model validation of furling wind turbines and to help understand small wind turbine loads. This report will familiarize the user with the scope of the SWRT test and support the use of these data. In addition to describing all the testing details and results, the report presents an analysis of the test data and compares the SWRT test data to simulation results from the FAST aeroelastic simulation model.

  14. Market experiences with small wind turbines

    International Nuclear Information System (INIS)

    Van Deijl, T.J.

    1990-01-01

    An overview is given of the marketing experiences of Lagerwey Windturbines with the exploitation of small wind turbines. Attention is paid to the market mechanisms which effect the sale and implementation of small wind turbines: payback of surplus power, provincial and regional subsidies, grid connection costs, energy prices, and flexible solutions for grid connections. Also problems with municipalities with regard to regulations or construction licenses are discussed. Some recommendations are given to stimulate the market for small wind turbines. 1 fig., 1 ref

  15. Lightning protection system for a wind turbine

    Science.gov (United States)

    Costin, Daniel P [Chelsea, VT; Petter, Jeffrey K [Williston, VT

    2008-05-27

    In a wind turbine (104, 500, 704) having a plurality of blades (132, 404, 516, 744) and a blade rotor hub (120, 712), a lightning protection system (100, 504, 700) for conducting lightning strikes to any one of the blades and the region surrounding the blade hub along a path around the blade hub and critical components of the wind turbine, such as the generator (112, 716), gearbox (708) and main turbine bearings (176, 724).

  16. Combustion modeling in advanced gas turbine systems

    Energy Technology Data Exchange (ETDEWEB)

    Smoot, L.D.; Hedman, P.O.; Fletcher, T.H. [Brigham Young Univ., Provo, UT (United States)] [and others

    1995-10-01

    The goal of the U.S. Department of Energy`s Advanced Turbine Systems (ATS) program is to help develop and commercialize ultra-high efficiency, environmentally superior, and cost competitive gas turbine systems for base-load applications in the utility, independent power producer, and industrial markets. Combustion modeling, including emission characteristics, has been identified as a needed, high-priority technology by key professionals in the gas turbine industry.

  17. Diagnosis and Supervision of Industrial Gas Turbines

    OpenAIRE

    Larsson, Emil

    2012-01-01

    Monitoring of industrial gas turbines is of vital importance, since it gives valuable information for the customer about maintenance, performance, and process health. The performance of an industrial gas turbine degrades gradually due to factors such as environment air pollution, fuel content, and ageing to mention some of the degradation factors. The compressor in the gas turbine is especially vulnerable against contaminants in the air since these particles are stuck at the rotor and stator ...

  18. Method and apparatus for wind turbine braking

    Science.gov (United States)

    Barbu, Corneliu [Laguna Hills, CA; Teichmann, Ralph [Nishkayuna, NY; Avagliano, Aaron [Houston, TX; Kammer, Leonardo Cesar [Niskayuna, NY; Pierce, Kirk Gee [Simpsonville, SC; Pesetsky, David Samuel [Greenville, SC; Gauchel, Peter [Muenster, DE

    2009-02-10

    A method for braking a wind turbine including at least one rotor blade coupled to a rotor. The method includes selectively controlling an angle of pitch of the at least one rotor blade with respect to a wind direction based on a design parameter of a component of the wind turbine to facilitate reducing a force induced into the wind turbine component as a result of braking.

  19. Turbine flow diagram of Paks-1 reactor

    International Nuclear Information System (INIS)

    Vancso, Tamas

    1983-01-01

    Computer calculations and programs are presented which inform the operators on the effect projected on the turbine and thermal efficiency of the modification in the flow diagram and in the starting parameters of the power cycle. In the program the expansion line of steam turbine type K-220-44 and the thermo-technical parameters of the elements of the feed-water heater system are determined. Detailed degree calculations for turbine unit of high pressure can be made. (author)

  20. Small wind turbines - Technical sheet

    International Nuclear Information System (INIS)

    2015-02-01

    This publication first proposes an overview of the technical context of small wind turbines (from less than 1 kW to 36 kW). It discusses issues related to mast height, indicates the various technologies in terms of machine geometry (vertical or horizontal axis), of mast and foundations, of mechanism of orientation with respect to the wind. It also outlines that power curves are not always reliable due to a lack of maturity of techniques and technologies. Other issues are discussed: wind characteristics, and the assessment of the national potential source. The next parts address the regulatory and economic context, environmental impacts (limited impact on landscape, noise), propose an overview of actors and market (supply and demand of small wind turbines in the USA and in France, actors involved in the chain value in France), and give some recommendations for the development of small wind turbines in France. The last part proposes a technical focus on self-consumption by professional in rural areas (production and consumption in farms)