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Multi-Harmonic RF Control System for J-PARC RCS

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... M. Taylor, T. Kurt Kyser. (2009) Feather isotope analysis discriminates age-classes of Western, Least, and Semipalmated sandpipers when plumage ... ...

Science.gov (United States)

... M. Taylor, T. Kurt Kyser. (2009) Feather isotope analysis discriminates age-classes of Western, Least, and Semipalmated sandpipers when plumage ... ...

Science.gov (United States)

... M. Taylor, T. Kurt Kyser. (2009) Feather isotope analysis discriminates age-classes of Western, Least, and Semipalmated sandpipers when plumage ... ...

Science.gov (United States)

... M. Taylor, T. Kurt Kyser. (2009) Feather isotope analysis discriminates age-classes of Western, Least, and Semipalmated sandpipers when plumage ... ...

UK PubMed Central (United Kingdom)

Several avian species show a bright carotenoid-based coloration during spring and following a period of duller coloration during the previous winter, despite carotenoids presumably being fully deposited...Full Text Available

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... perform the inspection in the extremely limited space between adjacent blades and at the blade root, miniature eddy current probes were developed ...

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Short communication

British Library Electronic Table of Contents (United Kingdom)

Harmonics bred from loads are mainly odd order because the current waveforms have half-wave symmetry. Since the even harmonics are negligibly small, they generally are not measured in electric power systems. However, even harmonics were measured at a 500/275/154 kV substation in Hokuriku Electric Power Company after a transmission line fault was corrected. The even harmonics caused malfunctions of protective digital relays because the relays used 4th harmonics at the input filter as the automatic supervisory signal. This paper describes mechanisms of generation of the even harmonics by comparing the measured waveforms with the ATP-EMTP simulation results. Analysis of these results has clearly shown that there are three different mechanisms of generation of even harmonics. The first mechani...

Energy Technology Data Exchange (ETDEWEB)

This paper describes a simple analysis procedure that transforms a set of beamline orbit data into a set of harmonic orbits of first, second, and third order or higher. Each harmonic orbit can be studied individually to identify errors of the specific order with minimum interference from other orders. Effectively these are orbits caused by kicks, due to harmonic errors, propagated through linear lattice. Examples from accelerator study will be presented. The application and inherent limitations of this analysis procedure are discussed.

International Nuclear Information System (INIS)

We report the first experimental achievement of a storage ring free-electron laser (FEL) oscillation on the third harmonic in the near-infrared region. The FEL gain was evaluated as 0.029% per mA. The measured linewidth of the third-harmonic FEL was less than that of the fundamental FEL, and the measured pulse width of the third-harmonic FEL was wider than that of the fundamental FEL. A higher-harmonic FEL should be developed not only to enhance the wavelength region of the FEL but also to vary the characteristics of an FEL micropulse. (author)

Science.gov (United States)

An experimental investigation of heat transfer characteristics for various configurations of air jets impinging on the leading edge inner surface of a gas turbine blade wall is presented. Three configurations were investigated, namely a slot jet, a round ...

Energy Technology Data Exchange (ETDEWEB)

In recent years very good experience has been accumulated with self-supporting low-pressure blades. Today blades are constructed up to a length of 1060 mm (50 Hz) or 1360 mm (25 Hz). In this process modern computational methods from aerodynamics and also from mechanics are employed. The further development of computer technology also permits new methods, for example the use of curved fixed blading as well as the optimization of existing designs. (orig.).

Science.gov (United States)

Experiments contributing to the understanding of the aerodynamics of airfoils operating in the vertical axis wind turbine (VAWT) environment are described. These experiments are ultimately intended to reduce VAWT cost of energy and increase system reliability. They include chordwise pressure surveys, circumferential blade acceleration surveys, effects of blade camber, pitch and offset, blade blowing, and use of sections designed specifically for VAWT application.

Science.gov (United States)

This report discusses the following topics on superconductivity: nonlinearities in hard superconductors such as surface impedance of a type II superconductimg half space and harmonic generation and intermodulation due to alternating transport currents; and nonlinearities in superconducting weak links such as harmonic generation by a long Josephson Junction in a superconducting slab.

Science.gov (United States)

... pulses by a 50/50 beamsplitter and recombined in space and in time inside a wafer of KDP crystal which generates a second harmonic of the ...

Science.gov (United States)

... and flashtube. Unfortunately, we had insufficient laser intensity to use the harmonic from a KDP crystal as a monitor. This ...

International Nuclear Information System (INIS)

An explicite PN solution of the multi-dimensional homogeneous neutron transport equation is given by expanding the angular flux into a series of geometry-independent spherical harmonics operators. An algorithm is developed for representing the spherical harmonic operators in orthogonal curvilinear coordinates. The general formulae are applied to two-dimensional spherical geometry; detailed P3 formulae are given. (orig.).

CERN Document Server

A generalized relativistic harmonic oscillator for spin 1/2 particles is studied. The Dirac Hamiltonian contains a scalar, $S$, and a vector, $V$, quadratic potentials in the radial coordinate, as well as a tensor potential, $U$, linear in $r$. Setting either or both combinations $\\Sigma=S+V$ and $% \\Delta=V-S$ to zero, analytical solutions for bound states of the corresponding Dirac equations are found. The eigenenergies and wave functions are presented and particular cases are discussed, devoting a special attention to the non-relativistic limit and the case $\\Sigma=0$, for which pseudospin symmetry is exact. We also show that the case $U=\\Delta=0$ is the most natural generalization of the non-relativistic harmonic oscillator. The radial node structure of the Dirac spinor is studied for several combinations of harmonic oscillator potentials, and that study allows us to explain why nuclear intruder levels cannot be ...

Energy Technology Data Exchange (ETDEWEB)

In this report the effects of harmonics in marine power systems is discussed and a comparison is given between the most typical converter types, including pulse width modulated drives, load commutated inverters and cycloconverters. The effect of harmonic distortion on the power system equipment and loads is first briefly discussed. Special attention is given to the circumstances in the low voltage distribution system, where general load equipment is connected. In addition to the total harmonic distortion the effect of voltage deviation to the supply quality is also considered. The origin of harmonics in the load currents of the three converter types is then considered. The differences between the converters are outlined, and the most typical spectra are presented. The possible means for reducing the harmonic distortion are also studied. The solutions considered are the increasing of ...

International Nuclear Information System (INIS)

A statistical evaluation of rotor blade damage in axial steam turbines affords an insight into the extent of the repair costs incurred and reveals the types of defects and shortcomings which cause such damage. The great amount of rotor blade damage discovered during control inspections will surprise even many turbine experts. The statistical evaluation is followed by a review of the more frequent causes of damage and their characteristic features, illustrated on the basis of practical examples. This contribution is intended as an aid to both the manufacturers and operators of steam turbines in preventing the oft almost classic types of faults which constantly recur. (orig.).

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Eckert, B., "Axial Kompressoren und Radial Kompressoren," Springer. Verlag, Berlin, 1953. 3. Lebot, Y., et al., "Theoretical and Experimental Determination ...

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lytical Comparison of Turbine-Blade Cooling System Designed for a. TurboJet Engine Operat- at Supersonic Speed and Altitude. I1 -. Air-C~Oling Systems. ...

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turbine (VAWT) is given, followed by a short history of its ... represents the most cost-effective blade for the Darneus-type VAWT. (Author). A79-14322 ...

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Theoretical and experimental research efforts in evaluating an innovative concept for vertical axis wind turbines (VAWT) are described. The concept is that of using straight blades composed of circulation controlled airfoil sections. The theoretical analysis has been developed to determine the unsteady lift and moment characteristics of multiple-blade cross-flow wind turbines. To determine the drag data needed as input to the theoretical analysis, an outdoor test model VAWT has been constructed; design details, instrumentation, and calibration results are reported. Initial testing is with fixed pitch blades having cross-sections of conventional symmetrical airfoils. Costs of building the test model are included, as well as estimates for blades constructed with composite materials. These costs are compared with those of other types of wind turbines.

Science.gov (United States)

We have calculated the on-axis spectrum of spontaneous radiation emitted by an electron moving along a planar undulator that has a magnetic profile along the axis that approximates a square wave. (This could be obtained in practice by driving a ferromagnetic undulator into saturation by excessive current in the windings.) We find considerable enhancement of the harmonic radiation spectrum. We compare the harmonic power emitted by an electron moving through an undulator having a sine-wave field profile with the radiation emitted from an undulator having a square-wave profile; the latter is approximated by the first three Fourier components of the undulator magnetic field profile along the axial direction. Examples are computed for 40MeV electrons taking K < 1, for spontaneous radiation emitted along the axis of the system. The emission at harmonics f > 1 is greatly enhanced for the approximate square-wave magnetic ...

Energy Technology Data Exchange (ETDEWEB)

A thesis is presented on improving the understanding of the fatigue properties of wood and fatigue failure mechanisms in the design of wind turbine blades. Three main areas were researched: the effect of R ratio on fatigue life, the effect of moisture on fatigue life and the development of cumulative damage laws. Tests were carried out on mainly four-ply laminates. Recommendations to future work are outlined. (U.K.).

Science.gov (United States)

The vibration behavior of turbomachine bladings is described, and the behavior of different kinds of coupled low pressure stages was experimentally investigated. Besides purely stationary flow conditions, conditions were also considered where pulsating fl...

Science.gov (United States)

Natural laminar-flow (NLF) airfoils are those which can achieve significant extents of laminar flow (greater than or equal to 30% chord) solely through favorable pressure gradients. Studies have shown that vertical-axis wind turbines (VAWTs) using NLF sections as blade elements have the potential of producing energy at a significantly lower cost (approx. =20%) than turbines of current design. Sandia National Laboratories (SNL) is now in the process of procuring a blade set for its 17-m-diameter research turbine which will use NLF sections as blade elements. This paper describes the design of this blade set. The blade set design began with the definition of a family of three approximately 50% chord NLF sections (15, 18, and 21% t/c). These definitions involved numerically establishing airfoil contours giving section characteristics anticipated to be favorable in the VAWT context and ...

Energy Technology Data Exchange (ETDEWEB)

A confocal microscopy imaging system was devised to selectively detect Second harmonic signals generated by biological tissues. Several types of biological tissues were examined using this imaging system, including human teeth, bovine blood vessels, and chicken skin. All these tissues generated strong second harmonic signals. There is considerable evidence that the source of these signals in tissue is collagen. Collagen, the predominant component of most tissues, is known to have second order nonlinear susceptibility. This technique may have diagnostic usefulness in pathophysiological conditions characterized by changes in collagen structure including malignant transformation of nevi, progression of diabetic complications, and abnormalities in wound healing.

Energy Technology Data Exchange (ETDEWEB)

There is a renewed interest in straight wing vertical axis wind turbines (SW-VAWT) which are usually installed on the roofs of high buildings in cities, urban areas and high mountain areas for independent electric power supply. SW-VAWTs have the advantages of simple design and low cost, as well as wind direction independence compared to the horizontal system. However, when SW-VAWTs are installed in cold regions, ice, snow and other attachments can affect its performance. In this study, clay was attached to the leading edge of the blade surface to determine how the performance of SW-VAWTs are affected by the mechanism of icing. Wind tunnel tests were used to study the rotational performance and power performance of the turbine blades. Icing prevention was also investigated. The attachment of clay on the leading edge of blade surface made the rotational performance of the SW-VAWT worse. The attachment of clay on the leading ...

Energy Technology Data Exchange (ETDEWEB)

This paper introduces recent instances of polymerizers for highly viscous liquid needed in the field of synthetic resin and synthetic fiber. A horizontal twin-shaft type polymerizer has two horizontally rotating shafts with stirring blades of spectacle-shaped type, which are arranged at a 90 [degree] phase difference. As they rotate, they scrape highly viscous liquid sticking to the surface inside the polymerizer and on the rotating shafts. This polymerizer is capable of processing highly viscous liquid up to about 2000 Pa[center dot]s. A lattice-type twisting blade polymerizer is a vertical-type reactor and features a special stirring blade capable of stirring highly viscous liquid up to 5000 Pa[center dot]s This polymerizer has no central rotating shaft so that highly viscous liquid does not stick on it. A sloped blade-type thin-film evaporator has spiral blades in the ...

Science.gov (United States)

A computational fluid dynamics (CFD) is coupled with a computational structural dynamics (CSD) to simulate the unsteady rotor flow with aeroelasticity effects. An unstructured upwind Navier-Stokes solver was developed for this simulation, with 2nd order time-accurate dual-time stepping method for temporal discretization and low Mach number preconditioning method. For turbulent flows, both the Spalart-Allmaras and Menter's SST model are available. Mesh deformation is achieved through a fast dynamic grid method called Delaunay graph map method for unsteady flow simulation. The rotor blades are modeled as Hodges & Dowell's nonlinear beams coupled flap-lag-torsion. The rotorcraft computational structural dynamics code employs the 15-dof beam finite element formulation for modeling. The structure code was validated by comparing the natural frequencies of a rotor model with UMARC. The flow and structure codes are coupled tightly with information exchange several ...

UK PubMed Central (United Kingdom)

The geographical arrangement of people on the surface of the earth is approximated by a mathematical equation of 361 terms. This is a convenient form for comparison with other distributions and for...Full Text Available

Science.gov (United States)

... 3004505040***, MEDICAMENTS, DOSED, VITAMINS, MULTIPLE, OTHER COMBINATIONS, FD3***. 3104100000**, CARNALLITE, SYLVITE AND OTHER CRUDE POTASSIUM SALTS, FD3**. ...

Energy Technology Data Exchange (ETDEWEB)

Computer simulations and experiments indicate that we can shape the infrared picosecond pulses of the Mark III FEL in amplitude, frequency, and phase. Strongly modulated fundamental and second harmonic pulses have been generated by operating the Mark III FEL in the regime of strong sideband growth. In this paper, we present the results of simulations and experiments for second harmonic generation with fundamental inputs from 2 to 3 {mu}m.

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This paper describes nonlinear effect recognized in Vibroseis data. Harmonics is a wave of frequency in integer factors generated in association with basic sweep vibrated by Vibroseis. Harmonics is generated because vibration in the vicinity of seismic source contains nonlinear terms. Seismic exploration using the reflection method often discusses propagation of seismic waves hypothesized as a linear phenomenon. Vibroseis data analysis, however, requires evaluation of the effect of the harmonics on accuracy. Vibroseis investigation measures may be taken by eliminating n-order harmonics by using the phase control method, and generating seismic source sweep in which the phase is shifted by 180/(n-1) each time in order to leave the basic sweep. Methods to increase the sweep length include a method to expel strain to a location outside the range of the subject travel time. Up-sweep (a sweep changing from ...

Energy Technology Data Exchange (ETDEWEB)

A numerical package called RESID has been assembled to calculate the residual stresses in VAWT blades induced during cold forming. Using a strength of materials - elementary beam theory approach, RESID models the material response with a bilinear stress-strain curve, and the cross-sectional geometry with an array of area increments. Through an iterative solution procedure residual stresses are predicted for a specified final radius of curvature or applied bending moment. RESID results are compared to theoretical solutions for simple geometries and with MARC Finite element results for VAWT blade geometries. Calculating residual stress levels, determining acceptable residual stress levels, and a method of reducing residual stresses are discussed. A complete listing and sample run are included in the appendicies.

British Library Electronic Table of Contents (United Kingdom)

Low pressure turbine blades (LPT) made by investment casting from intermetallic titanium aluminide alloys for aero-engine applications in lengths between 200 and 400 mm require very demanding and sophisticated process for their manufacturing. Middle line shrinkage porosity along the airfoil and dimensional tolerances by near-net-shape casting are especially sensitive issues concerning Quality assurance. Nevertheless the urgency to manufacture safer environmental-friendly high performance aero-engines requires the introduction of new high performance components like LPT blades made of TiAl, which are about 50% lighter than their nickel-based counterparts. The present work is based on process engineering taking into account different melting and casting technologies in order to develop a dep...

Science.gov (United States)

Sandia National Laboratories has developed a family of airfoils specifically designed for use in the equatorial portion of a Vertical-Axis Wind Turbine (VAWT) blade. An airfoil of that family has been incorporated into the rotor blades of the DOE/Sandia 34-m diameter VAWT Test Bed. The airfoil and rotor design process is reviewed. Comparisons with data recently acquired from flow visualization tests and from the DOE/Sandia 34-m diameter VAWT Test Bed illustrate the success that was achieved in the design. The economic optimization model used in the design is described and used to evaluate the effect of modifications to the current Test Bed blade. 1 tab., 11 figs., 13 refs.

Science.gov (United States)

STRESS. VIBRATION DISTRIBUTION FATIGUE FOD. BLADE. X. X. X. X. HUB. X. X. X. SPINNER. X. X. X. Figure 21. - Large scale component test matrix. ...

Energy Technology Data Exchange (ETDEWEB)

The desirable performance attributes of a vertical axis wind turbine (VAWT) include high starting torque, high peak efficiency, broad operating range and a reasonable insensitivity to the parameters that define its operation. The theoretical performance of three variable pitch mechanisms for VAWT are compared. Cycloturbines use cam devices or gears to impose a sinusoidal pitch regime. In the mass-stabilised system, pitch is determined by the interplay of two opposing moments on the blades. These two mechanisms are compared with Aeropitch, a hypothetical pitch control system in which stabilising moments are related to the blade relative velocity. (Author)

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This annex provides a description of the sensor schemes and the non-destructive testing (NDT) methods that have been investigated in this project. Acoustic emission and fibre optic sensors are described in some detail whereas only the key features of well-established NDT methods are presented. Estimates of the cost of different sensor systems are given and the advantages and disadvantages of the different schemes is discussed. (au)

CERN Document Server

The interaction energies between the different types of bases of a single strand of DNA molecule have been calculated. Using these original values of energies the harmonic behavior of a number of base patterns of DNA has been studied. In view of the great interest aroused by the discovery of the role of the telomere segment of the DNA in the replication process and its possible link with the aging process, we have investigated, with simple models, the harmonic behavior of the telomeric pattern of bases as well as the thermodynamic response in the biological system. With these results a conclusion on the probable role of the telomeric pattern on aging has also been drawn. Here the calculated values of harmonic frequencies of the telomeric pattern of bases and of other possible patterns show that the telomeric pattern is associated with the highest vibrational frequency among all patterns of base combinations at the ...

Energy Technology Data Exchange (ETDEWEB)

The A(..pi../sup +/,/sup 3/He)B reaction near threshold is studied in a model where the pion is absorbed by an /sup 4/He constituent of the target nucleus. The predictions of this model using harmonic oscillator cluster wave functions agree semi-quantitatively with the experimental data on the inverse reaction.

Science.gov (United States)

... Rev. Lett., vol. 42, no. 24, pp. 1625-1628, June 1979. 3 ... Trans. Plasma Science, vol. PS-10, no. 1, pp. 55-58, March 1982. ...

UK PubMed Central (United Kingdom)

The temporal fine structure (TFS) of sound contributes significantly to the perception of music and speech in noise. The evaluation of new strategies to improve TFS delivery in cochlear implants (CIs)...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

New technologies make multi-megajoule glass lasers economically feasible. Laser architectures using harmonic switchout, target plane holographic injection, phase conjugation, continuous apodization and higher amplifier efficiencies have been devised. A plan for a multi-megajoule laser which can be built for an acceptable cost relies on manufacturing economies of scale and the demonstration of the new technologies presented here. These include continuous pour glass production, rapid harmonic crystal growth, switching of large blocks of power using larger capcaitors packed more economically and by using large identical parts counts.

International Nuclear Information System (INIS)

Coherent x-ray production by a seeded free electron laser (FEL) is important for next generation synchrotron light sources. The authors examine the feasibility and features of FEL emission seeded by a high-order harmonic generation (HHG) of an infrared laser. In addition to the intrinsic FEL chirp, the longitudinal profile and spectral bandwidth of the HHG seed are modified significantly by the FEL interaction well before saturation. This smears out the original attosecond pulselet structure. The authors introduce criteria for this smearing effect on the pulselet and the stretching effect on the entire pulse. They discuss the noise issue in such a seeded FEL.

Science.gov (United States)

Blade fatigue life is an important element in determining the economic viability of the Vertical-Axis Wind Turbine (VAWT). A principal source of blade fatigue is thought to be the stochastic (i.e., random) aerodynamic loads created by atmospheric turbulence. This paper discusses the development of a model for the simulation of these stochastic loads, given the rotor geometry, operating conditions, and assumed turbulence properties. A Double-Multiple-Streamtube analysis is employed, which includes the effects of wind shear. Reynolds number variations, different airfoil sections and chord lengths along the blade span, and an empirical model for dynamic stall effects. Calculations are presented for the VAWT 34-m Test Bed currently being assembled at Bushland, Texas. Time histories of the loads, as well as their Fourier spectra, are presented and discussed. An unexpected finding is that the average output power is predicted to ...

Science.gov (United States)

Sandia National Laboratories has erected a research oriented, 34- meter diameter, Darrieus vertical axis wind turbine near Bushland, Texas. This machine, designated the Sandia 34-m VAWT Test Bed, is equipped with a large array of strain gauges that have been placed at critical positions about the blades. This manuscript details a series of four-point bend experiments that were conducted to validate the output of the blade strain gauge circuits. The output of a particular gauge circuit is validated by comparing its output to equivalent gauge circuits (in this stress state) and to theoretical predictions. With only a few exceptions, the difference between measured and predicted strain values for a gauge circuit was found to be of the order of the estimated repeatability for the measurement system.

Energy Technology Data Exchange (ETDEWEB)

In nuclear reactor safety research, the question of the possible consequences of delayed core reflood during severe accidents or anticipated transient without scram transients in boiling water reactors (BWRs) has been raised. One can envisage a very low probability accident scenario leading to core uncovery and core heat-up, followed by control blade melting and subsequential delayed reflooding of the core with unborated water before its degradation. Reflooding of the hot core causes significant increases in the peak heating, melting, and hydrogen production rates, thus increasing the probability of core degradation. However, as has been established, debris beds formed from shattered fuel rods and quenched fuel melt will be undermoderated. The reflood process of a voided, intact core was examined using the TRAC/BFI CODE.

Science.gov (United States)

The class of vertical axis wind turbines (VAWT) investigated use curved, fixed-pitch blades of constant section rigidly attached to a vertical rotating tower. Qualitatively, the main advantages of the VAWT over more conventional, propeller-type machines are the elimination of yaw controls, the placement of mechanical equipment at ground level, its amenability to simple, low-cost blade fabrication techniques, and aerodynamic stall characteristics which eliminate the need for active pitch control devices. The main disadvantages relative to modern propeller machines are a somewhat lower aerodynamic efficiency (about 10 percent lower), the limited ability of the rotor to self-start, and generally lower rotor operating RPM's, which leads to higher torque capacity requirements for the drive train.

Energy Technology Data Exchange (ETDEWEB)

We provide an example in which the Heisenberg and the Schroedinger pictures of quantum mechanics give different results, thus confirming the statement of P.A.M. Dirac that the two pictures may lead to inequivalent results. We consider a one-dimensional nonrelativistic charged harmonic oscillator (frequency {omega}{sub 0} and mass m), and take into account the action of the radiation reaction and the vacuum electromagnetic forces on the charged oscillator. We show that the Heisenberg picture gives the correct value, {Dirac_h}{omega}{sub 0}/2, for the ground state energy of the harmonic oscillator in both cases of classical and quantized vacuum fields. In the case of the Schroedinger picture, considering classical vacuum fields, and using a simple calculation for the classical radiation reaction force that is valid in the limit of large mass (mc{sup 2} >> {Dirac_h}{omega}{sub 0}), we obtain the value {Dirac_h}{omega}{sub 0} for the ...

International Nuclear Information System (INIS)

Economic and safe operation of nuclear power plants requires reliable steam turbines with high efficiencies. The progress in flow mechanics achieved over the past few years has allowed the use of powerful methods of flow calculation in developments of new blading with greatly enhanced efficiencies. Thanks to the latest manufacturing techniques, the newly developed blading systems can be produced at low cost. Next to progress in flow mechanics, also the broadbased use of advanced finite-element calculations resulted in a more thorough grasp of the many problems associated with structural mechanics assessment of steam turbine components. The theoretical methods have been supplemented by comprehensive efforts in fracture mechanics and experimental materials studies, thus helping to create a reliable knowledge base which will help to avoid the dreaded stress corrosion cracking phenomenon, in components of steam turbines. The measures introduced to ...

Science.gov (United States)

Double streamtube codes model the curved blade (Darrieus-type) vertical-axis wind turbine (VAWT) as a double actuator-disk arrangement (one disk for the upwind half of the rotor and a second disk for the downwind half) and use conservation of momentum pri...

International Nuclear Information System (INIS)

Among the investigations conducted on the space shuttle flight STS 3 March 1982 was an experiment in which a 1-keV, 100-mA electron gun was pulsed at 3.25 and 4.87 kHz. The resultant waves were measured with a broadband plasma wave receiver. At the time of flight the experimental setup was unique in that the electron beam was square wave modulated and that the shuttle offered relatively long times for in situ measurements of the ionospheric plasma response to the VLF pulsing sequences. In addition to electromagnetic response at the pulsing frequencies the waves exhibited various spectral harmonics as well as the unexpected occurrence of satellite lines around those harmonics. Both phenomena occurred with a variety of different characteristics for different pulsing sequences.

British Library Electronic Table of Contents (United Kingdom)

A prerequisite for a sensible estimate of moisture induced stresses in timber members is an accurate prediction of the members' moisture states during their service life. There are, however, an infinite number of possible moisture states for an arbitrary timber member in a natural varying climate. The naturally varying humidity is possible to describe as harmonic cycles, with different periods, superimposed. This work presents realizations of envelop curves over the possible moisture states in a timber member for some carefully chosen harmonic humidity variations. The calculations, on which the realizations were made, are based on a fully coupled transport model including a model for the influential sorption hysteresis of wood. A format containing required information suitable for assessin...

CERN Document Server

The unavoidable irreversible losses of power in a heat engine are found to be of quantum origin. Following thermodynamic tradition a model quantum heat engine operating by the Otto cycle is analyzed. The working medium of the model is composed of an ensemble of harmonic oscillators. A link is established between the quantum observables and thermodynamical variables based on the concept of canonical invariance. These quantum variables are sufficient to determine the state of the system and with it all thermodynamical variables. Conditions for optimal work, power and entropy production show that maximum power is a compromise between the quasistatic limit of adiabatic following on the compression and expansion branches and a sudden limit of very short time allocation to these branches. At high temperatures and quasistatic operating conditions the efficiency at maximum power coincides with the endoreversible result. The optimal compression ratio varies from the square ...

Energy Technology Data Exchange (ETDEWEB)

The Superconducting Super Collider uses approx. =9600 dipole magnets. The magnets have been carefully designed to exhibit minimal magnetic field harmonics. However, because of superconductor magnetization effects, iron saturation and conductor/coil positioning errors, certain harmonic errors are possible and must be corrected by use of multipole correctors called trim coils. For the most efficient use of axial space in the magnet, and lowest possible current, a distributed internal correction coil design is planned. The trim coil assembly is secured to the beam tube, a uhv tube with special strength, size, conductivity and vacuum. The report details the SSC trim coil/beam tube assembly specifications, history, and ongoing development.

Energy Technology Data Exchange (ETDEWEB)

A fast multipole transformation is adapted to the evaluation of summations that occur in global climate calculations when transforming between spatial and spherical harmonic representations. For each summation, the timing of the fast multipole transformation scales linearly with the number of latitude gridpoints, but the timing for direct evaluations scales quadratically. In spite of a larger computational overhead, this scaling advantage renders the fast multipole method faster than direct evaluation for transformations involving greater than approximately 300 to 500 gridpoints. Convergence of the fast multipole transformation is accurate to machine precision. As the resolution in global climate calculations continues to increase, an increasingly large fraction of the computational work involves the transformation between spatial and spherical harmonic representations. The fast multipole transformation offers a significant reduction in ...

Energy Technology Data Exchange (ETDEWEB)

The nuclear shapes of transitional Mo isotopes are calculated by means of a model based on the cranking approximation and the Strutinksy method. The recent experimental results of the high-spin spectroscopy and lifetime measurement of [sup 87]Mo are studied in detail and explained by the evolution of the [gamma]-deformation with the quasiparticle configurations. The shape calculations with the modified-harmonic-oscillator potential give a critical neutron number N [>=] 47 for the spherical shape of the Mo isotopes. (orig.)

International Nuclear Information System (INIS)

A new channel of nonlinear ionization of quantum system in a strong laser field is discussed. The probability of spontaneous radiation decay from the ground state in a short-range potential to the final Volkov wave function, is calculated by the first order of the perturbation theory. It is shown that this process at high intensities of the laser field will be comparable with the high harmonic generation. (orig.)

Science.gov (United States)

In an earlier paper (Phys. Rev. Lett. 66, 41 (1991)), we calculated both the dielectric constant ({epsilon}{sub {infinity}}) and the nonlinear optical susceptibilities for second-harmonic generation ({chi}{sup (2)}) in the static limit for AlP, AlAs, GaP, and GaAs in the local-density approximation with and without a self-energy correction in the form of a scissors operator,'' including local-field effects. In this paper, we expand our presentation of this calculation. Agreement with experiment to within 15% for the nonlinear susceptibility is demonstrated where experiments are available (GaP and GaAs); the dielectric constants are in no worse than 4% agreement with experiment. The virtual hole'' contributions are reformulated to avoid large numerical cancellations in the case of near degeneracies. The virtual electron'' terms dominate over the virtual hole'' terms by about one order of ...

Energy Technology Data Exchange (ETDEWEB)

Goal was developing optical methods for study of dynamic processes at the electrode/electrolyte interface. In the past year, optical second harmonic generation was used for time-resolved measurements of thallium deposition on Cu(111). The studies of carrier dynamics in photo-excited materials have involved both steady-state and picosecond time-resolved luminescence measurements following photoexcitation of the semiconductor material.

International Nuclear Information System (INIS)

The case of spontaneous radiation of channeled ultrarelativistic particles is considered when the dipolarity condition is not satisfied. The change of the particle longitudinal velocity affecting the maximum radiation frequency is included. The angular and frequency characteristics of the radiation for superhigh energies are studied for the first time. It is shown that there is an optimum energy at which the radiation density is maximum. The influence of the angle at which electrons enter a crystal and of the beam divergence on the radiation is investigated. The problem of quasichanneled particle radiation and also the radiation in axis-plane transitions are considered. (author).

International Nuclear Information System (INIS)

Coherent oscillator radiation is considered. A comparison is made with classical particle radiation with gauss distribution. Decay probability for coherent state in spontaneous radiation is estimated. The method suggested for describing harmonic oscillator allows to separate the effect of classical field radiation from quantum description of particle state within the framework of a self-consistent quantum mechanical problem.

Energy Technology Data Exchange (ETDEWEB)

The aerodynamic behavior of a vertical axis wind turbine (VAWT) is analyzed by means of 2D particle image velocimetry (PIV), focusing on the development of dynamic stall at different tip speed ratios. The VAWT has an unsteady aerodynamic behavior due to the variation with the azimuth angle {theta} of the blade's sections' angle of attack, perceived velocity and Reynolds number. The phenomenon of dynamic stall is then an inherent effect of the operation of a VAWT at low tip speed ratios, impacting both loads and power. The present work is driven by the need to understand this phenomenon, by visualizing and quantifying it, and to create a database for model validation. The experimental method uses PIV to visualize the development of the flow over the suction side of the airfoil for two different reference Reynolds numbers and three tip speed ratios in the operational regime of a small urban wind turbine. The field-of-view of the experiment covers ...

Science.gov (United States)

The Wind Energy Research Division of Sandia National Laboratories has been funded by the Wind/Ocean Technology Division of the Department of Energy (DOE) to design and build a 34-meter diameter Vertical Axis Wind Turbine (VAWT). The turbine design incorporates the results of recent VAWT research in aerodynamics and structural dynamics. Initial system concept studies identified several blade options that met the required power rating of 500 kW. The final blade and rotor configurations were chosen based on finite element calculations that determined the turbine modes of response, their frequency of vibration, and stress levels. For parked survival turbine components were designed to with stand the loading of a 150 mph (67.0 m/s) wind coupled with maximum cable tensions. Specific areas of design discussed include the rotor, cables, bearings, brakes, and foundations. Construction of the turbine is in progress at this time and anticipated completion ...

International Nuclear Information System (INIS)

Vertical thin film evaporators have been used to concentrate and dry solutions because their rotating swing blades prevent scale from being deposited on the heated surfaces. Powdering capacity of the vertical thin film evaporator was examined experimentally for drying applications of radioactive liquid waste generated from nuclear power plants. As a result, it was found that the powdering capacity increased with the blade rotation, changing significantly in the low ratational region and scarcely in the high rotational region. The powdering capacity in the high rotational region was restricted by the lack of heat flux which was theoretically evaluated for the concentrating process. As the critical factor in the low rotational region was not clear, a visual test apparatus was made to observe flow patterns in the evaporator, and a powdering model was obtained. This model showed that powdering process was obstructed when the liquid film lost its ...

Energy Technology Data Exchange (ETDEWEB)

A one-way coupling system between the plant simulator TRAC/BF1-ENTREE and the subchannel code with the improved cross flow model, NASCA, has been developed. Based on a scenario of turbine trip tests in the Peach Bottom Unit 2, the wide and rapid reactivity insertion transient induced by the system pressure rise was calculated. The pin power distribution in hot bundles was re-constructed considering heterogeneity of the fuel bundle. When the neighboring control blade is withdrawn, NASCA predicted that the steady-state bundle exit void distribution was nearly flat with regardless of the pin power distribution. However, void distributions in the middle and lower bundle regions became complicated depending on the pin power and the two-phase flow regime in each subchannel. The pin power distribution rapidly changed according to traveling of control blades. However, influence in the void distribution was delayed and damped due to the fuel heat ...

International Nuclear Information System (INIS)

The McMaster Neutron Radiography Facility (MNRF) is fortunate to own the only Real-Time Neutron Radiography system in Canada. Current research at the MNRF involves the visualization of gas-liquid and gas-solid two-phase flow in complex channels, such as nuclear fuel channels, using light water, heavy water, freon-134A, slurries, and other fluids. Other research at the MNRF has examined single-phase flow, material purity, film deposition, turbine blades, and automotive parts.

Energy Technology Data Exchange (ETDEWEB)

This presentation is primarily about unsteady aerodynamics in relation to wind turbines. It is divided into three very distinct sections: (1) Basic unsteady aerodynamics; (2) VAWT performance modelling and (3) Passive stall regulation of VAWTs. The aim of the presentation is to illustrate that, if desired, future wind turbine blades could be aerodynamically tailored to exploit the unsteady nature of the VAWT flow with far greater confidence and insight than has been hitherto possible. To this effect, the collaborating British research teams and, in particular, VAWT Ltd. have assembled sufficient knowledge for such a conclusion to be made. (author).

Energy Technology Data Exchange (ETDEWEB)

Blade fatigue life is an important element in determining the economic viability of the Vertical-Axis Wind Turbine (VAWT). A principal source of blade fatigue is thought to be the stochastic (i.e., random) aerodynamic loads created by atmospheric turbulence. This report describes the theoretical background of the VAWT Stochastic Aerodynamic Loads (VAWT-SAL) computer code, whose purpose is to numerically simulate these random loads, given the rotor geometry, operating conditions, and assumed turbulence properties. A Double-Multiple-Stream Tube (DMST) analysis is employed to model the rotor's aerodynamic response. The analysis includes the effects of Reynolds number variations, different airfoil sections and chord lengths along the blade span, and an empirical model for dynamic stall effects. The mean ambient wind is assumed to have a shear profile which is described by either a power law or a logarithmic variation ...

International Nuclear Information System (INIS)

The thermodynamics of the Sr-Si system is of fundamental importance for the understanding of eutectic modification of Al-Si alloys. At the same time, strontium silicides have recently been found to have potential applications in electronic devices. Renewed research efforts have led to a re-evaluation of the phase equilibria in this system, resulting in the discovery of previously undetected stable intermetallic compounds. In this work, we investigate the finite temperature thermodynamic properties of the stable (and metastable) Sr-Si intermetallics. The vibrational properties of the intermetallic compounds are calculated within harmonic theory, with quasi-harmonic corrections to account for the effects of thermal expansion. The total free energies of the compounds are computed considering vibrational and electronic contributions, as well as weak anharmonic corrections. The ground state of the system is predicted and compared to previous ...

International Nuclear Information System (INIS)

The advances in laser technology have made available very short and intense laser pulses which can be used to seed a high-gain single-pass free-electron laser (FEL) amplifier. With these seed pulses, a regime of the FEL interaction where the radiation evolution is simultaneously dominated by nonlinear effects (saturation) and time-dependent effects (slippage) can be explored. This regime is characterized by the propagation of a solitary wavelike pulse where the power of the optical wave grows quadratically with time, its pulse length decreases and the spectral bandwidth increases. We analyze the interplay between the field and particle dynamics of this propagation regime which was studied before and termed super-radiance. Furthermore we analyze the properties of the strong higher-order harmonic emission from this wave and its behavior when propagating in a cascade FEL. The super-radiant pulse is indeed capable of passing through the stages of a cascade FEL and to ...

Energy Technology Data Exchange (ETDEWEB)

A highly efficiency partial smoothing method is proposed to be used for inverters for 40W class household fluorescent inverters. In this system, the input current from the commercial AC power source is accumulated in a capacitor with comparatively small capacity as the electric charge, and then the lamp circuit is driven by the inverter utilizing the charging voltage of the capacitor and the charging voltage of the separately prepared partial smoothing capacitor. By this method, the RF harmonic components in the supply current can be decreased to improve the power factor with no complicated feedback controlling device. In addition, comparatively small capacity coils and capacitors can be used. The structure of the circuit and the operation of this proposed method are described, and the operational characteristic of the prototype circuit and the result of analysis are shown. Furthermore, problems and improving method of the actual circuit are investigated by an ...

International Nuclear Information System (INIS)

Total quality management strategy and the worldwide introduction of the DIN/ISO 9000 (EN 29 000) series of standards have given new impetus to traditional quality assurance. The most important change must surely be seen in the holistic approach of total quality management and its strict orientation towards customer requirements and satisfaction. International codes and standards for the nuclear industry will also have to be brought into line as part of the process of harmonizing quality assurance system standards. One possible approach is simply to specify a supplementary 'delta' of nuclear-specific requirements to be appended to the broad range of conventional requirements. It is a particular feature of quality-assured procedures in Germany that product and/or component related quality requirements and quality verifications are defined in the specifications of the architect engineer so that full implementation of the requirements from the design phase through to ...

British Library Electronic Table of Contents (United Kingdom)

As one of the evolutionary oldest parts of the brain, the diencephalon evolved to harmonize changing environmental conditions with the internal state for survival of the individual and the species. The pioneering work of physiologists and psychologists around the middle of the last century clearly demonstrated that the hypothalamus is crucial for the display of motivated behaviors, culminating in the discovery of electrical self-stimulation behavior and providing the first neurological hint accounting for the concepts of reinforcement and reward. Here we review recent progress in understanding the role of the lateral hypothalamic area in the control of ingestive behavior and the regulation of energy balance. With its vast array of interoceptive and exteroceptive afferent inputs and its equ...

Energy Technology Data Exchange (ETDEWEB)

At the conclusion of polarized proton commissioning in February 1986, protons with an average polarization of 45%, momentum of 21.7 GeV/c, and intensity of 2 x 10/sup 10/ protons per pulse, were extracted to an external polarimeter at the Brookhaven AGS. In order to maintain this polarization, five intrinsic and nearly forty imperfection depolarizing resonances had to be corrected. An apparent interaction between imperfection and intrinsic resonances occurring at very nearly the same energy was observed and the correction of imperfection resonances using ''beat'' magnetic harmonics discovered in the previous AGS commissioning run was further confirmed.

International Nuclear Information System (INIS)

To investigate the magnetic fluctuations and for further transport study, the poloidal and radial magnetic field measurement is conducted on the Sino United Spherical Tokamak (SUNIST). Auto-power spectral density indicates that the magnetic fluctuation energy mainly concentrates in the frequency region lower than 10 kHz. The magnetic field oscillations, which are characterized by harmonic frequencies of 40 kHz, are observed in the scrape-off layer; by contrast, in the plasma core, the magnetic fluctuations are of Gaussian type. The time-frequency profiles show that the poloidal magnetic fluctuations are temporally intermittent. The autocorrelation calculation indicates that the fluctuations in decorrelation time vary between the core and the edge. (authors)

International Nuclear Information System (INIS)

The electromagnetic properties of a prototype gravitational wave detector, based on two coupled superconducting microwave cavities, were tested. The radio-frequency (rf) detection system was carefully analysed. With the use of piezoelectric crystals small harmonic displacements of the cavity walls were induced and the parametric conversion of the electromagnetic field inside the cavities explored. Experimental results of bandwidth and sensitivity of the parametric converter versus stored energy and voltage applied to the piezoelectric crystal are reported. A rf control loop, developed to stabilize phase changes on signal paths, gave a 125 dBc rejection of the drive mode on a time scale of 1 h.

Energy Technology Data Exchange (ETDEWEB)

Palmer Drought Severity Index (PDSI) monthly data are analyzed, building on a previous study that investigated the influence of the El Nino/Southern Oscillation (ENSO) on US streamflow. Harmonic analysis is performed using data from 1,035 selected climatological stations, allowing observation of the biennial tendency in climate data. With the middle twelve months defined as the El Nino year (0), an idealized first harmonic fit to a 24-month ENSO composite is computed for each station. By plotting the first harmonic vectors of each station, regions of similar, or coherent, response are identified. The regions identified using PDSI data represent wet conditions in the Gulf of Mexico (Gm1 and GM2) and central (C) US, and dry conditions in the Pacific northwest (PNW) and northeast (NE) US. The PNW region exhibits the strongest interrelationship between ENSO and extreme drought events. Comparing PDSI data results with other ...

Energy Technology Data Exchange (ETDEWEB)

I present a promising route to harmonize distance measurements based on clump giants and RR Lyrae stars. This is achieved by comparing the brightness of these distance indicators in three environments: the solar neighborhood, Galactic bulge and Large Magellanic Cloud (LMC). As a result of harmonizing the distance scales in the solar neighborhood and Baade's Window, I derive the new absolute magnitude of RR Lyrae stars, M{sub v}(RR) at [Fe/H] = -1.6 (0.59 {+-} 0.05, 0.70 {+-} 0.05). Being somewhat brighter than the statistical parallax solution, but fainter than typical results of the main sequence fitting to Hipparcos data, these values of M{sub V}(RR) favor intermediate or old ages of globular clusters. Harmonizing the distance scales in the LMC and Baade's Window, I show that the most likely distance modulus to the LMC, {mu}{sub LMC} is in the range 18.24 - 18.44. The Hubble constant of about 70 km/s/Mpc ...

Science.gov (United States)

Field surveys were conducted to assess the community annoyance potential from electromagnetic interference to television reception (TVI) and acoustic emissions associated with the operation of a Darrieus-type, vertical axis wind turbine (VAWT). The type and extent of interference to nearby television reception was evaluated using a 17 meter VAWT. A series of measurements of observed interference levels were made at a number of sites in the turbine vicinity employing the locally available VHF and UHF television signals as sources. A simple theoretical model was developed for analyzing the TVI produced by the Darrieus turbine. Using this model in conjunction with the field measurements, it was found the Darrieus/VAWT produces the same amount of interference on the lower VHF channels as a horizontal axis turbine with a comparably sized blade scattering area, but less on all other channels.

British Library Electronic Table of Contents (United Kingdom)

Abstract:- Two motorcycle riders lost control of their vehicle, fell, and hit a guardrail, which acted as a blade and led to a rapid, fatal outcome. In one case, the high velocity of the body at the time of the impact resulted in complete detachment of the trunk. Reconstruction of the accident dynamics enabled the guardrail post to be identified as the means of injury in both cases. The two accidents occurred over a short period of time, highlighting a dangerous phenomenon that in less severe cases is presumably associated with different degrees of survivor disability. The accidents deserve mention, because a different design of the impact surface of the guardrail post might have prevented the lethal outcome. There is an urgent need for legislators to pass regulations that modify crash bar...

Science.gov (United States)

The local heat transfer coefficient distribution of a square channel with two opposite ribbed walls was determined. The square channel was connected to a sudden contraction entrance in order to simulate the inlet condition of the turbine blade cooling passages. The test channel was heated by thin stainless steel foils with a thickness of 0.000025 m, and instrumented with 180 thermocouples. The brass ribs of a square cross-section were glued periodically, in line, onto the top and bottom walls of the foil-heated channel in patterns to achieve the desired spacing and angle-of-attack. The local heat transfer coefficients on the smooth side and the ribbed side walls, at the channel entrance and the downstream regions, were measured for eight rib configurations and three Reynolds numbers (Re = 10,000, 30,000, and 60,000).

Energy Technology Data Exchange (ETDEWEB)

The application of the phased array technique was limited to heavy and thick wall components as present in the nuclear industry. With the improvement of the equipment and probes other application areas are now open for the phased array technique, e.g. the inspection of the turbine blade root, weld inspection in a wall thickness range between 12 and 40 mm, inspection of aircraft components, inspection of spot welds or inspection of concretes. The aim of the use of phased array techniques has not been changed related to the first applications, i.e. the adaptation of the sound beam to the geometry by steering the angel of incidence or the skewing angle as well as the focussing of sound fields. Due to the fact, that the new applications of the phased array techniques in some cases don't leave the laboratories for the time being, the examples of this contribution will focus applications with practical background. (orig.)

International Nuclear Information System (INIS)

The implementation of wind energy conversion systems in the built environment renewed the interest and the research on Vertical Axis Wind Turbines (VAWT), which in this application present several advantages over Horizontal Axis Wind Turbines (HAWT). The VAWT has an inherent unsteady aerodynamic behavior due to the variation of angle of attack with the angle of rotation, perceived velocity and consequentially Reynolds number. The phenomenon of dynamic stall is then an intrinsic effect of the operation of a Vertical Axis Wind Turbine at low tip speed ratios, having a significant impact in both loads and power. The complexity of the unsteady aerodynamics of the VAWT makes it extremely attractive to be analyzed using Computational Fluid Dynamics (CFD) models, where an approximation of the continuity and momentum equations of the Navier-Stokes equations set is solved. The complexity of the problem and the need for new design approaches for VAWT for the built environment has driven the ...

International Nuclear Information System (INIS)

This report summarizes work performed by Argonne National Laboratory (ANL) on fatigue and environmentally assisted cracking (EAC) in light water reactors (LWRs) during the six months from October 1993 to March 1994. EAC and fatigue of piping, pressure vessels, and core components in LWRs are important concerns in operating plants and as extended reactor lifetimes are envisaged. Topics that have been investigated include (a) fatigue of low-alloy steel used in piping, steam generators, and reactor pressure vessels, (b) EAC of wrought and cast austenitic stainless steels (SSs), and (c) radiation-induced segregation and irradiation-assisted stress corrosion cracking (IASCC) of Type 304 SS after accumulation of relatively high fluence. Fatigue tests have been conducted on A302-Gr B low-alloy steel to verify whether the current predictions of modest decreases of fatigue life in simulated pressurized water reactor water are valid for high-sulfur heats that show environmentally enhanced ...

CERN Document Server

We study the dynamics of states perturbatively expanded about a harmonic system of loop quantum cosmology, exhibiting a bounce. In particular, the evolution equations for the first and second order moments of the system are analyzed. These moments back-react on the trajectories of the expectation values of the state and hence alter the energy density at the bounce. This analysis is performed for isotropic loop quantum cosmology coupled to a scalar field with a small but non-zero constant potential, hence in a regime in which the kinetic energy of matter dominates. Analytic restrictions on the existence of dynamical coherent states and the meaning of semi-classicality within these systems are discussed. A numerical investigation of the trajectories of states that remain semi-classical across the bounce demonstrates that, at least for such states, the bounce persists and that its properties are similar to the standard case, in which the moments of the states are ...

Science.gov (United States)

Spontaneous radiation emitted from relativistic electrons undergoing betatron motion in a plasma-focusing channel is analyzed, and applications to plasma wake-field accelerator experiments and to the ion-channel laser (ICL) are discussed. Important similarities and differences between a free electron laser (FEL) and an ICL are delineated. It is shown that the frequency of spontaneous radiation is a strong function of the betatron strength parameter a(beta), which plays a role similar to that of the wiggler strength parameter in a conventional FEL. For a(beta) > or approximately 1, radiation is emitted in numerous harmonics. Furthermore, a(beta) is proportional to the amplitude of the betatron orbit, which varies for every electron in the beam. The radiation spectrum emitted from an electron beam is calculated by averaging the single-electron spectrum over the electron distribution. This leads to a frequency broadening of the radiation spectrum, which places ...

CERN Document Server

We study perturbations of a Schwarzschild black hole in Chern-Simons modified gravity. We begin by showing that Birkhoff's theorem holds for a wide family of Chern-Simons coupling functions, a scalar field present in the theory that controls the strength of the Chern-Simons correction to the Einstein-Hilbert action. After decomposing the perturbations in spherical harmonics, we study the linearized modified field equations and find that axial and polar modes are coupled, in contrast to general relativity. The divergence of the modified equations leads to the Pontryagin constraint, which forces the vanishing of the Cunningham-Price-Moncrief master function associated with axial modes. We analyze the structure of these equations and find that the appearance of the Pontryagin constraint yields an overconstrained system that does not allow for generic black hole oscillations. We illustrate this situation by studying the case characterized by a canonical choice of the ...

Energy Technology Data Exchange (ETDEWEB)

At Los Alamos, we are building a free-electron laser (FEL) for industrial, medical, and research applications. This FEL, which will incorporate many of the new technologies developed over the last decade, will be compact in size, robust, and user-friendly. Electrons produced by a photocathode will be accelerated to 20 MeV by a high-brightness accelerator and transported using permanent-magnet quadrupoles and dipoles. They will form an electron beam with an excellent instantaneous beam quality of 10 {pi} mm mrad in transverse emittance and 0.3% in energy spread at a peak current up to 300 A. Including operation at higher harmonics, the laser wavelength extends form 3.7 {mu}m to 0.4 {mu}m. In this paper, we will describe the project and the programs to date. 10 refs., 10 figs., 1 tab.

British Library Electronic Table of Contents (United Kingdom)

Abstract Results of numerous experiments conducted over the past 15-years by using behavioural as well as brain imaging methods have shown that musical expertise influences brain anatomy, brain functions and behaviour. The musician- brain is thus considered as a very good model of brain plasticity. Moreover, many results have demonstrated that musical expertise not only impacts on music processing but also on several aspects of speech processing including lexical pitch, sentence intonation and the metric structure of words. Conversely, recent results indicated that linguistic expertise with tone or quantity languages such as Mandarin Chinese, Thai, Finnish and Japanese, influences the processing of harmonic tones and musical intervals. We discuss possible interpretations of these findings ...

Science.gov (United States)

Sensitive and quick-response nonlinear inductance characteristics are found for high Tc superconducting (YBa/sub 2/Cu/sub 3/O/sub 7-chi/) disk cores at 77K in which soft magnetic BH hysteresis loops are observed. Various quick response magnetic devices such as modulators, amplifiers and sensors are built using these cores. The magnetizing frequency can be set to more than 20 MHz, which is difficult for conventional ferromagnetic bulk materials such as Permalloy amorphous alloys and ferrite. New quick-response fluxgate type magnetic-field sensors are made using ac and dc voltage sources. The former is used for second-harmonic type sensors, while the latter is for voltage-output multivibrator type sensors. Stable and quick-response sensor characteristics were obtained for two-core type multivibrators.

Energy Technology Data Exchange (ETDEWEB)

In a laser system for converting infrared laser light waves to visible light comprising a source of infrared laser light waves and means of harmoic generation associated therewith for production of light waves at integral multiples of the frequency of the original wave, the improvement of said means of harmonic generation comprising a crystal having the chemical formula X.sub.2 Y(NO.sub.3).sub.5 .multidot.2 nZ.sub.2 o wherein X is selected from the group consisting of Li, Na, K, Rb, Cs, and Tl; Y is selected from the group consisting of Sc, Y, La, Ce, Nd, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Al, Ga, and In; Z is selected from the group consisting of H and D; and n ranges from 0 to 4.

Energy Technology Data Exchange (ETDEWEB)

The electron cyclotron resonance layer in a tokamak, {omega}={omega}{sub c}(r), is not accessible by the extraordinary wave from the low field side, because it is shielded by a cutoff layer. However, a X-mode launched with a nonzero toroidal angle propagates at the cutoff parallel to the magnetic field and has a circular polarization. Therefore it can already at the cutoff layer interact efficiency with electrons via the Doppler shifted resonance. The driven current can be substantially higher than that driven by the second harmonic X-mode. The applicability of this current drive scheme is limited to rather low values of {omega}{sub p}{sup 2}/{omega}{sub c}{sup 2}, but may be of interest for high magnetic field devices. (author)

International Nuclear Information System (INIS)

We present and characterize a very efficient optical device that employs the plasma mirror technique to increase the contrast of high-power laser systems. Contrast improvements higher than 104 with 50% transmission are shown to be routinely achieved on a typical 10 TW laser system when the pulse is reflected on two consecutive plasma mirrors. Used at the end of the laser system, this double plasma mirror preserves the spatial profile of the initial beam, is unaffected by shot-to-shot fluctuations, and is suitable for most high peak power laser systems. We use the generation of high-order harmonics as an effective test for the contrast improvement produced by the double plasma mirrors. (authors)

British Library Electronic Table of Contents (United Kingdom)

The (simplified) Backus? Problem (BP) consists in finding a harmonic function u on the domain exterior to the three dimensional unit sphere S, such that u tends to zero at infinity and the norm of the gradient of u takes prescribed values g on S. Except for a change of sign, the solution is not unique in general. However, there is uniqueness of solutions in the class of functions with the additional property that the radial component of the gradient of u on S is nonpositive. This is the geodetically relevant case. If a solution u with this property exists, then u is the maximal solution of the problem (and -u the minimal one). In this paper we propose a method of successive approximations to get this particular solution of BP and prove the convergence for functions g close to a constant fu...

CERN Document Server

This contribution reviews a selection of findings on atomic density functions and discusses ways for reading chemical information from them. First an expression for the density function for atoms in the multi-configuration Hartree--Fock scheme is established. The spherical harmonic content of the density function and ways to restore the spherical symmetry in a general open-shell case are treated. The evaluation of the density function is illustrated in a few examples. In the second part of the paper, atomic density functions are analyzed using quantum similarity measures. The comparison of atomic density functions is shown to be useful to obtain physical and chemical information. Finally, concepts from information theory are introduced and adopted for the comparison of density functions. In particular, based on the Kullback--Leibler form, a functional is constructed that reveals the periodicity in Mendeleev's table. Finally a quantum similarity measure is ...

International Nuclear Information System (INIS)

The new nonlinear optical crystal Rb3V5O14 has been synthesized by solid state reaction and characterized by single-crystal X-ray diffraction, IR and thermogravimetric analysis. The crystal Rb3V5O14 crystallizes in the trigonal system with space P31m (No. 157), a=b=8.7134(12) A, c=5.2807(11) A and ?=90o, ?=90o, ?=120o, Z=1, ?=3.516 g/cm3. It is a layered structure that is very flat and strongly parallel to c. The V5O14 layer structure consists of corner-linked square and triangular pyramids. The layers are separated by Rb+ ions, which fit equally well on the V5O14 layer. The Kurtz powder SHG measurement, using 1064 nm radiation, showed that the second-harmonic generation efficiency of Rb3V5O14 is about two times that of KDP. -- Graphical abstract: The new nonlinear optical crystal Rb3V5O14 has been synthesized by solid state reaction and characterized by single-crystal X-ray diffraction, IR and thermogravimetric analysis. The crystal Rb3V5O14 crystallizes in the ...

Energy Technology Data Exchange (ETDEWEB)

To heighten durability and safety of materials/parts for undersea oil drilling, the development of ceramic base materials was made by developing function harmony type process technology which harmonizes on a high grade contrary characteristics and various functions. The paper summed up the fiscal 1997 results. In the design of system formation, computational simulation technology was developed to the composite process and the diploid system. The development of multifunction simultaneous manifestation materials was trially made by the higher nano structure process. A study was made of control of microstructures of porous materials and matrix filling by the gas phase precipitation control. Proposed were selective control of grain growth from species crystals and the columnar particle orientation laminated structure of simultaneous manifestation of strength and toughness. By composite precipitation reaction control, studied were simultaneous dispersion of whisker and ...

Energy Technology Data Exchange (ETDEWEB)

The complete determination of stroke/throughput curves at steam turbines for arbitrary valve positions usually only follows after the fundamental layout of the control valves, of the possible nozzle segments and of the turbine blading. A general fundamental equation and some design norms based on it are presented which may serve already before a fluidic layout of the turbine in detail as an optimizing predetermination of the properties concerning pressure loss and control statics of the metering components in the admission area. (orig.) [Deutsch] Die vollstaendige Bestimmung der Hub-/Durchsatzkurven an Dampfturbinen fuer beliebige Ventilstellungen erfolgt ueblicherweise erst nach der Grundauslegung der Stellventile, etwaiger Duesensegmente und der Turbinenbeschaufelung. Es werden eine allgemeine Grundgleichung und einige auf ihr aufbauende Entwurfsregeln angegeben, die zu einer optimierenden Vorabbestimmung der druckverlustbezogenen regelstatischen Eigenschaften ...

Energy Technology Data Exchange (ETDEWEB)

Proactive qualification is today an integral part of the development process for steam turbines used in steam and combined cycle power plants. By providing experimentally based `random` variables, such as the steam path efficiency and blading reliability, it makes a valuable contribution to the economic `random` variables of the power plant, e.g. the rate of return, as viewed by the customer. One of the areas in which proactive product and process qualification plays an important role is the development of LP steam paths. (orig.) [Deutsch] Die proaktive Qualifikation ist heute fester Bestandteil des Entwicklungsprozesses bei Dampfturbinen, die fuer den Einsatz in Dampf- und Kombikraftwerken bestimmt sind. Sie leistet mit Hilfe experimentell ermittelter `Zufalls`-Variablen, wie z.B. Wirkungsgrad der Fluten und Zuverlaessigkeit der Beschaufelungen, einen wertvollen Beitrag zu den fuer die Kunden wichtigen wirtschaftlichen `Zufalls`-Variablen des Kraftwerks, wie etwa ...

Energy Technology Data Exchange (ETDEWEB)

During the last 15 years cycles with CO{sub 2} capture have been in focus, due to the growing concern over our climate. Often, a natural gas fired combined cycle with a chemical absorption plant for CO{sub 2} capture from the flue gases have been used as a reference in comparisons between cycles. Neither the integration of the steam production for regeneration of amines in the combined cycle nor the off-design behaviour of such a plant has been extensively studied before. In this paper, the integration of steam production for regeneration of the amines is modelled at design load and studied in off-design conditions for a combined cycle. Different ambient conditions and part-load strategies and their influence on the cycle performance are also examined. Of particular interest is a novel strategy with the possibility of longer life of gas turbine blading, with marginal loss in efficiency. The off-design performance of the combined cycle is modelled in a rigorous way ...

Energy Technology Data Exchange (ETDEWEB)

This report summarizes work performed by Argonne National Laboratory on fatigue and environmentally assisted cracking (EAC) in light water reactors from January 1997 to June 1997. Topics that have been investigated include (a) fatigue of carbon, low-alloy, and austenitic stainless steels (SSs) used in reactor piping and pressure vessels, (b) irradiation-assisted stress corrosion cracking of Types 304 and 304L SS, and (c) EAC of Alloys 600 and 690. Fatigue tests were conducted on ferritic and austenitic SSs in water that contained various concentrations of dissolved oxygen (DO) to determine whether a slow strain rate applied during various portions of a tensile-loading cycle is equally effective in decreasing fatigue life. Slow-strain-rate-tensile tests were conducted in simulated boiling water reactor (BWR) water at 288 C on SS specimens irradiated to a low fluence in the Halden reactor and the results were compared with similar data from a control-blade sheath and ...

Energy Technology Data Exchange (ETDEWEB)

Actinosynnema mirum Hasegawa et al. 1978 is the type species of the genus, and is of phylogenetic interest because of its central phylogenetic location in the Actino-synnemataceae, a rapidly growing family within the actinobacterial suborder Pseudo-nocardineae. A. mirum is characterized by its motile spores borne on synnemata and as a producer of nocardicin antibiotics. It is capable of growing aerobically and under a moderate CO2 atmosphere. The strain is a Gram-positive, aerial and substrate mycelium producing bacterium, originally isolated from a grass blade collected from the Raritan River, New Jersey. Here we describe the features of this organism, together with the complete genome sequence and annotation. This is the first complete genome sequence of a member of the family Actinosynnemataceae, and only the second sequence from the actinobacterial suborder Pseudonocardineae. The 8,248,144 bp long single replicon genome with its 7100 protein-coding and 77 RNA ...

Energy Technology Data Exchange (ETDEWEB)

Wind power is an increasingly significant renewable energy resource, producing no environmentally damaging C0{sub 2} emissions. The efficient production of electricity by wind turbines relies on aerodynamics: aerodynamics of wind turbines provides the fundamental solutions to efficient wind turbine design. Following a historical introduction, Part 1 of Aerodynamics of Wind Turbines is concerned with basic rotor aerodynamics, while Part 2 deals with structural aspects of the wind turbine and calculation of the loads on it. 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. Aerodynamics of Wind Turbines is an essential reference for both engineering students and ...

Energy Technology Data Exchange (ETDEWEB)

The Control Rod Drive(CRD) nozzles for PWR nuclear power plants(NPP) house the control rod drives. The number of nozzle penetrations range from the mid-30's to over 100 in each reactor head. The integrity of CRD nozzles is very important, because the primary pressure boundary is established with the J-groove weld joining the nozzle to the head clad surface. The Alloy 600 PWSC CRD nozzle leaks discovered in the fall of 2000 and spring of 2001 in several US plants. Therefore the NRC has recommended a more proactive effort by US utilities to inspect similarly susceptible nozzles in all US plants. The primary safety concern is circumferential cracks that can permit the nozzles to separate from the head at high velocity and produce a large-break leak in the reactor vessel. A secondary concern is head leakage from any through-wall cracks in the nozzle or J-groove weld area. Numerous inspection and repair tools have been developed to address CRD nozzle inspection and repair issues. ...

Energy Technology Data Exchange (ETDEWEB)

This paper presents a technique for speed control three-phase induction motor using the pulse width modulation (PWM), in open loop while maintaining the tension for constant frequency. The technique is adapted from a thesis entitled 'Control of the three-phase induction motor, using discrete PWM generation, optimized and synchronized', where studies are presented aimed at their application in home appliances, to eliminate mechanical parts, replaced by low cost electronic control, thus having a significant reduction in power consumption. Initially the experiment was done with the Intel 80C31 micro controller. In this paper, the PWM modulation is implemented using a PIC micro controller, and the speed control kept a low profile, based on tables, synchronized with transitions and reduced generation of harmonics in the network. Confirmations were made using the same process of building tables, but takes advantage of the program of a RISC device.

CERN Document Server

The quantum $N$-body problem is studied in the context of nonrelativistic quantum mechanics with a one-dimensional deformed Heisenberg algebra of the form $[\\hat x,\\hat p]=i(1+\\beta \\hat p^2)$, leading to the existence of a minimal observable length $\\sqrt\\beta$. For a generic pairwise interaction potential, analytical formulas are obtained that allow to estimate the ground-state energy of the $N$-body system by finding the ground-state energy of a corresponding two-body problem. It is first shown that, in the harmonic oscillator case, the $\\beta$-dependent term grows faster with $N$ than the $\\beta$-independent one. Then, it is argued that such a behavior should be observed also with generic potentials and for $D$-dimensional systems. In consequence, quantum $N$-body bound states might be interesting places to look at nontrivial manifestations of a minimal length since, the more particles are present, the more the system deviates from standard quantum ...

International Nuclear Information System (INIS)

We consider spatially homogeneous (but generally non-isotropic) cosmologies in the recently proposed Horava-Lifshitz gravity and compare them to those of general relativity using Hamiltonian methods. In all cases, the problem is described by an effective point particle moving in a potential well with exponentially steep walls. Focusing on the closed-space cosmological model (Bianchi type IX), the mixmaster dynamics is now completely dominated by the quadratic Cotton tensor potential term for a very small volume of the universe. Unlike general relativity, where the evolution toward the initial singularity always exhibits chaotic behavior with alternating Kasner epochs, the anisotropic universe in Horava-Lifshitz gravity (with parameter #lambda# > 1/3) is described by a particle moving in a frozen potential well with fixed (but arbitrary) energy E. Alternating Kasner epochs still provide a good description of the early universe for very large E, but the evolution appears to be ...

International Nuclear Information System (INIS)

The oscillation experiment of free-electron laser (FEL) was carried at the wave length 488 nm. The space and time properties and power of FEL were investigated. The typical macropulse structure indicated the time interval 20 ms and the pulse width 2 to 3 ms. About 1 ns was necessary to build up FEL. The space distribution of FEL showed beautiful TEM_0_0 mode, TEM_0_1 and TEM_0_2 mode. On the basis of data, 39 #mu#W average power was calculated at 2.9 mA accumulated current per bunch by integrating each response of pixel of CCD camera. The peak power was 1.2 W. In the oscillator, FEL power was average 1.2 W, peak 38 kW. On the electron beam, the stability of head tail was controlled by 6-pole-Quadrupole-6-pole (SQS) system made by an experimental basis. We succeeded the single set test, setting up single set in the ring. The characteristic properties of electron beam evaporation mirror of photo oscillator were studied and then new type photo oscillator to obtain large peak power was ...

Energy Technology Data Exchange (ETDEWEB)

The document describes the outcome of the CSN/CIEMAT-00 interlaboratory test comparison among environmental radioactivity laboratories. the exercise was organised according to the ISO-43 and the ISO/IUPAC/AOAC Harmonized Protocol for the proficiency testing of analytical laboratories. the test sample was a soil containing environmental levels of K-40, Ra-226, Ac-228, Sr-90, Cs-137, Cs-134, Pu (239-240) y Am-241. the Universidad Autonoma de Barcelona prepared the material and reported adequate statistical studies of homogeneity. The results of the exercise were computed for 30 participating laboratories, and their analytical performance was assessed using the u-score approach. A raised percentage of satisfactory laboratory performance has been obtained for all the analysis, being the best performance in gamma measurements. The exercise has drawn that several laboratories have difficulties in the evaluation of combined uncertainty, mainly in analysis involving ...

CERN Document Server

We summarize results of recent studies of heavy quarkonia correlators and spectral functions at finite temperatures from lattice QCD and systematic T-matrix studies using QCD motivated finite-temperature potentials. We argue that heavy quarkonia dissociation shall occur in the temperature range $1.2 \\le T_d/T_c \\le 1.5$ by the interplay of both screening and absorption in the strongly correlated plasma medium. We discuss these effects on the quantum mechanical evolution of quarkonia states within a time-dependent harmonic oscillator model with complex oscillator strength and compare the results with data for $R_{\\rm AA}/R_{\\rm AA}^{\\rm CNM}$ from RHIC and SPS experiments. We speculate whether the suppression pattern of the rather precise NA60 data from In-In collisions may be related to the recently discovered X(3872) state. Theoretical support for this hypothesis comes from the cluster expansion of the plasma Hamiltonian for heavy quarkonia in a strongly ...

Science.gov (United States)

This paper proposes an optimization algorithm to reduce the distortion produced in the loop-filter of Continuous-Time Sigma-Delta Modulators. The aim of the algorithm is to find the loop-filter implementation that minimizes distortion at the output of the modulator, by modifying the output swing of every integrator. The algorithm is implemented in Matlab as an evolutive searching. During each step of the searching, the algorithm evaluates the harmonical distortion of a tone when it is applied to the modulator with a certain loop-filter implementation. The output of the algorithm is an optimum linear state-space representation of the loop-filter. This particular state-space representation leads to minimum distortion at the output of the modulator when the loop-filter is implemented with some specific circuitry previously defined. As long as the search is of evolutive type, the solution represents a local minimum only. The algorithm computes a random guess solution ...

International Nuclear Information System (INIS)

This work aims at improving the understanding of the dynamics of a Free Electron Laser (FEL) based on a storage ring. A new phenomenon of saturation by the electron bunch transverse dimensions is pointed out, during the FEL operation with a magnetic optics ''low emittance''. A part of this thesis work concerns the study of the longitudinal dynamics of the FEL depending on a parameter: the detuning between the pass frequency of the electrons and the back and return frequency of the laser pulse in the optical cavity. This study shows that the FEL presents a pulsed or a steady state behavior depending on the detuning. Besides, a spectro-temporal behavior of the FEL is pointed out showing the FEL pulse substructures and holes in the spectrum. Another part of this work concerns the response of the resonant FEL system, when a perturbation is applied on the gain. Under the effect of a modulation, the FEL can present a periodic or chaotic regime. The analysis of these regimes shows that a ...

Energy Technology Data Exchange (ETDEWEB)

Operating the Stanford Linear Collider (SLC) at 120Hz repetition rate requires the presence of two bunches in both the electron and the positron damping ring. The {pi}-mode instability, a coupled bunch instability where the two bunches oscillate with a phase difference of 180{degrees}, had been observed in both rings with low current thresholds of 7{sup *}10{sup 9} particles per bunch. To avoid the instability, the RF system had to be operated in ways which in general reduced the cavity gap voltages and required constant operational attention. For the 1992 running cycle a passive cavity was installed and successfully tested. It is tuned to the frequency of the lower synchrotron oscillation sideband of an odd revolution harmonic. The impedance of the cavity then damps {pi}-mode oscillations very similar to the Robinson damping provided by the main RF cavities which damps O-mode synchrotron oscillations. In this report we describe the motivation and physical ...

International Nuclear Information System (INIS)

We consider the possibility of a cyclotron-autoresonance-maser (CARM) klystron configuration for accelerator applications as an alternative to the gyroklystron amplifier. The potential advantages, compared to gyroklystrons, include: 1) comparable efficiencies at lower values of the electron beam pitch ratio #alpha#, which should improve the beam quality and make the device substantially more stable against the excitation of parasitic mode, 2) operation far from cutoff, which should reduce the fields at cavity walls, allowing higher power operation, and 3) operation at lower magnetic fields for the same cyclotron harmonic number. However, there are two significant issues associated with the design of efficient, high-power CARMs. First, because of the higher value of k_Z, compared to gyroklystrons, CARMs are substantially more sensitive to parallel velocity spread (pitch-angle spread). Second, conventional cavities support a variety of near-cutoff modes, which can ...

International Nuclear Information System (INIS)

We describe a panoramic stigmatic spectrograph comprising a grazing-incidence toroidal mirror and a large-aperture free-standing transmission diffraction grating (5000 lines mm-1 ). Two spectrograph versions were constructed, with grazing angles of 7.6 and 40 and the short-wavelength spectral limits near 4 and 1.5 nm. The spectrograph aberrations were studied by numerical ray tracing. The spectrograph was used to record line and quasi-continuous spectra (1.5 - 30 nm) of multiply charged ions in a plasma generated by the second-harmonic pulses of an yttrium aluminate laser (Q = 0.15 J, ? = 5 ns, ? = 0.54 ?m, repetition rate = 0.5 Hz). In combination with a laser-produced plasma radiation source, the arrangement was used to characterise soft x-ray optical components and to generate collimated beams of polarised radiation in the 14 - 20 nm range. (laser applications and other topics in quantum electronics)

International Nuclear Information System (INIS)

A model for coherent fluctuations of the nuclear density including all nucleons in the fluctuation movement is formulated. The wave function of the flucton satisfies a Schroedinger-type equation in which the role of potential energy is played by the energy of the nuclear matter for the A nucleons. The appearance of high-momentum components in the one-particle momentum distribution is related to the volume fluctuations of the density. These fluctuations are supposed to be of coherent nature, i.e. all nucleons are involved in the motion. An explicit expression for the momentum distribution of the nucleons in "1"2C and "1"8"1Ta nuclei is obtained and compared with the phenomenological momentum distribution as well as with the results given by the model of a non-relativistic harmonic oscillator and by the Dirac equation in the self-consistent model. The differential cross-section of 1 GeV proton scattering by the "2"8Si, "3"2S, "4"0Ca, "4"8Ca, "5"8Ni, "2"0"8Pb are ...

Energy Technology Data Exchange (ETDEWEB)

The windmill industry in Denmark is currently confronted with making a choice between competing technologies so that the role of the stimulus of state subsidies for research has lately increased in importance. The Ministry of Energy, it is claimed, must be aware of this as possibilities for making use of research results are dictated by the market and competition. The industry is not sympathetic to the idea of state research contracts with specified goals for which manufacturers must produce a technical solution. Consultancy firms should work towards solving general problems which could help the industry as a whole. Wind turbines which are cheap to produce and operate are of more interest to industry than those which are technologically advanced or of a lighter construction. It is not thought to be advantageous to concentrate the allocation of subsidies on one key project chosen by the Ministry itself, such as the current intense interest in turbine blades. ...

Energy Technology Data Exchange (ETDEWEB)

The most developed systems for the generation of electricity from coal are the Integrated coal Gasification Combined Cycle (IGCC) and the Pressurized Fluidized Bed Combustion (PFBC) system. They both represent state-of-the-art technology and provide electric power at 41-46% LHV efficiency. However, the high level of complexity leads to lower reliability and higher costs. A simpler system, based on a coal-fired steam boiler integrated with a gas turbine, has been proposed. In such a plant, known as the externally fired combined cycle (EFCC), compressed air is heated indirectly in a heat exchanger located in the coal furnace. The hot air is then expanded in a turbine, and the exhaust is passed on to the coal furnace as preheated combustion air. Steam produced in the boiler generates additional power in a steam turbine. The exclusion of coal combustion products from the gas turbine avoids hot gas clean-up and turbine blade corrosion by coal ash. In order to obtain a ...

Energy Technology Data Exchange (ETDEWEB)

The capacity extension of additives was tested in a 200 cm/sup 2/bi-cell and a Zn powder moving-bed slurry. It was found that for the Type A additives in 12 M KOH, 25 g/l of silicate provided higher capacity than stannate, titanate and aluminate additives. The optimum concentration of sorbitol (a Type B additive that stabilizes polymeric chains involving ZnO) was found to be 15 g/l in 12 M KOH. A silicate and sorbitol combination added to Zn powder slurry in 12 M KOH provided a 20% increase in discharge capacity (195 Ah/l at 200 A/cm/sup 2/) compared to the maximum capacity obtained with silicate alone. A much lower capacity (74 Ah/l) was realized with silicate as Type C additive (precipitation of ZnO away from the Zn surface, for low KOH concentrations). The mechanisms of passivation and capacity extension were discussed and a model presented. The cell voltage and power densities were determined for the discharge process as a function of (a) current densities, (b) cathode depolarizer ...

Energy Technology Data Exchange (ETDEWEB)

Investigations show that nickel-based alloys (MAR M 247 CC, CM DS 247 L and CMSX-4) can be successfully brazened. Tensile tests of MAR M 247 CC samples brazened with foil brazing showed values comparable to those of the base material, some samples failed because of base material problems. Tests with powder mixes made up from commercial brazens and the base material CMSX-4 showed good wetting and a perfect microstructure similar to the base material. Tensile test values at RT (test temperature) and 850 degrees centigrade show pronounced scatter. Tensile tests at RT and 850 degrees centigrade are used to optimse brazing cycles for the types of brazen used (temperature, time). (orig.) [German] Die Untersuchungen haben gezeigt, dass es moeglich ist, Nickelbasislegierungen (MAR M 247 CC, CM DS 247 LC und CMSX-4) erfolgreich zu loeten. Die im Zugversuch erhaltenen Festigkeitswerte der mit folienfoermigen Lot geloeteten MAR M 247 CC Proben erreichten Werte nahe der Festigkeit des ...

Energy Technology Data Exchange (ETDEWEB)

This paper described a newly developed chipper device for mounting on Claas Jaguar chipper harvesters for short rotation forestry harvesting. It was designed by the Agriculture Engineering Research Unit of the Agricultural Research Council in Rome, Italy. The new rotor has a lower number of blades compared to standard rotors and has a different cutting angle and drum insertion. This study evaluated the particle-size distribution of wood chips produced by standard rotors compared to those with the experimental rotor. The objective was to distinguish the particle size distribution of chips produced using the two types of chippers in order to evaluate the influence of wooden species in the chip formation process. Tests were conducted using 860 and 890 Claas Jaguar chipper harvesters, both equipped with standard and CRA-ING rotors. The experiment was conducted on poplar cultivations on biennial shift and on arboreal cultivations. Compared to traditional rotors, CRA-ING ...

Energy Technology Data Exchange (ETDEWEB)

This book contains 10 lectures with the following subjects: On the effect of thermal pretreatment on the structure and creep behaviour of the alloy 800 H (V. Guttmann, J. Timm); Material properties of heat resistant ferritic and austenitic steels after cold forming (W. Bendick, H. Weber); Investigations for judging the working behaviour of components made of alloy 800 and alloy 617 under creep stress (H.J. Penkalla, F. Schubert); Creep behaviour of gas turbine materials in hot gas (K.H. Kloos et al.); Effect of small cold forming on the creep beahviour of gas turbine blades made of Nimonic 90 (K.H. Keienburg et al.); Investigations on creep fatigue alternating load strength of nickel alloys (G. Raule); Change of structure, creep fatigue behaviour and life of X20 Cr Mo V 12 1 (by G. Eggeler et al.); Investigations on thermal fatigue behaviour (K.H. Mayer et al.); Creep behaviour of similar welds of the steels 13 Cr Mo 4 4, 14 MoV 6 3, 10 Cr Mo 910 and GS-17 Cr Mo V ...

Energy Technology Data Exchange (ETDEWEB)

A home-made 3.1 kWh wind turbine that is promising to be the hottest new wind product to appear for home/farm users in some time, is described. The turbine is installed near a farm house in the high wind area of Mount Forest, Ontario. The turbine is hooked up to a four kilowatt Trace inverter charger which is coupled through a DC disconnect and C-60 charge controller to two sets of solar panels (seven panels of 120 W each by Solarex SX 120, and five panels by Sharp, each providing 1600 watt of solar power). The wind turbine and the solar panels, assisted by two 65-year old refurbished wind turbines, one bank of Gel Cell batteries, and an Onan 5 kW gas generator supply the electrical requirements of a seven member family in a 3400 square foot house. The new turbine is mounted on an 80-foot tower, has three eight foot Kevlar blades that produce a 17 foot overall sweep. The turbine weighs 615 lbs., produces 3.1 kW of pure power at just 310 rpms at a low start up wind ...

Energy Technology Data Exchange (ETDEWEB)

The Externally-Fired Combined Cycle (EFCC) offers a method for operating high-efficiency gas and steam turbine combined cycles on coal. In the EFCC, an air heater replaces the gas turbine combustor so that the turbine can be indirectly fired. Ceramic materials are required for the heat exchange surfaces to accommodate the operating temperatures of modern gas turbines. The ceramic air heater or heat exchanger is the focus of this program, and the two primary objectives are (1) to demonstrate that a ceramic air heater can be reliably pressurized to a level of 225 psia (1.5 MPa); and (2) to show that the air heater can withstand exposure to the products of coal combustion at elevated temperatures. By replacing the gas turbine combustor with a ceramic air heater, the cycle can use coal or other ash-bearing fuels. Numerous programs have attempted to fuel high efficiency gas turbines directly with coal, often resulting in significant ash deposition upon turbine components and corrosion or ...

Energy Technology Data Exchange (ETDEWEB)

Human senescence marker protein 30 (SMP30), which functions enzymatically as a lactonase, hydrolyzes various carbohydrate lactones. The penultimate step in vitamin-C biosynthesis is catalyzed by this enzyme in nonprimate mammals. It has also been implicated as an organophosphate hydrolase, with the ability to hydrolyze diisopropyl phosphofluoridate and other nerve agents. SMP30 was originally identified as an aging marker protein, whose expression decreased androgen independently in aging cells. SMP30 is also referred to as regucalcin and has been suggested to have functions in calcium homeostasis. The crystal structure of the human enzyme has been solved from X-ray diffraction data collected to a resolution of 1.4 {angstrom}. The protein has a 6-bladed {beta}-propeller fold, and it contains a single metal ion. Crystal structures have been solved with the metal site bound with either a Ca{sup 2+} or a Zn{sup 2+} atom. The catalytic role of the metal ion has been ...

Energy Technology Data Exchange (ETDEWEB)

The National Institute of Materials Science (NIMS) has utilized the in-house alloy design program to develop a 5{sup th} generation Ni-base single crystal superalloy, TMS-196 with superior high temperature creep, thermo mechanical fatigue (TMF) and oxidation resistance by incorporating further ruthenium (Ru) and chromium (Cr) content over the compositions of 4{sup th} generation superalloys. With Ru additions in advanced superalloys to enhance phase stability, higher content of refractory elements can be accommodated to provide further strengthening; the associated oxidation resistance can be improved by the increase in Cr additions. In present article, TMS-196 has been subjected to cyclic/isothermal oxidation tests at 1100 C and 900 C, creep at conditions between 800 C{proportional_to}1100 C/137MPa{proportional_to}735MPa and TMF cycles. Preliminary studies indicate that the surface of oxidized TMS-196 can exhibit continuous alumina layer attributing good oxidation resistance similar ...

Science.gov (United States)

Two branches of research are conducted in this thesis. The first deals with nonlinear combustion response as a mechanism for triggering combustion instabilities in solid rocket motors. A nonlinear wave equation is developed to study a wide class of combustion response functions to second-order in fluctuation amplitude. Conditions for triggering are derived from analysis of limit cycles, and regions of triggering are found in parametric space. Introduction of linear cross-coupling and quadratic self-coupling among the acoustic modes appears to be how the nonlinear combustion response produces triggering to a stable limit cycle. Regions of initial conditions corresponding to stable pulses were found, suggesting that stability depends on initial phase angle and harmonic content, as well as the composite amplitude, of the pulse. Also, dependence of nonlinear stability upon system parameters is considered. The second part of this thesis presents research for a ...

Energy Technology Data Exchange (ETDEWEB)

Temperature and concentration profiles of CO in a laminar, axisymmetric, premixed methane-air Bunsen flame are measured using line-of-sight diode laser absorption spectroscopy and computer tomographic (CT) reconstruction. Absorption spectra for P(20) (v=2<-1) and P(27) (v=1<-0) vibrotational transitions of CO were measured at 21 evenly spaced positions over a 1.33 cm span for a 1.3 cm radius flame. CT reconstruction algorithm was based on Fourier convolution. The tomographically reconstructed normalized transmission profiles derived from absorption spectra, in conjunction with a quantum mechanical model for vibrotational behavior of CO, yielded both temperature and concentration profiles. The Bunsen flame had 3 distinct zones: an inner rich-premixed flame zone, an outer non-premixed flame zone and an unburnt core region. The reconstructed temperature profile showed that the core region temperature was close to ambient and rapidly increased to adiabatic flame temperature at the ...

Energy Technology Data Exchange (ETDEWEB)

The current state and need for radiation protection training in Finland have been surveyed by the Radiation and Nuclear Safety Authority STUK. The survey sought to determine whether the current requirements for radiation protection training had been met, and to promote radiation protection training. Details of the scope and quality of present radiation protection training were requested from all educational institutes and organizations providing radiation protection training. The survey covered both basic and further training, special training of radiation safety officers, and supplementary training. The questionnaire was sent to 77 educational organization units, 66 per cent of which responded. Radiation workers and radiation safety officers were asked about radiation protection knowledge and needs for additional training. The questionnaire was sent to 880 radiation users and 170 radiation safety officers, 70 per cent of whom responded. The survey covered all professional groups and ...

Energy Technology Data Exchange (ETDEWEB)

After the transcription of the electricity directive in national legislations, the European electricity market appears to be a vast set of juxtaposed markets which are weakly connected at the level of their wholesale contracts compartment. Referring to the technological peculiarities of electricity as a commodity, the paper identifies the direct conditions of regional integration of the electricity markets, those which would favour cross-border trade and allow to be near the normal functioning of a regional commodity market. The infrastructure network dependence and the need of a stringent technical coordination necessitate to unify the operation of the different systems and the rules of access, or at the least to come near this unification by strong coordination. A second major condition, which is not fully debated, is the increasing connexion of short-term markets, via daily physical trade and emergence of a European financial market, which could trade various standardised contracts ...

Energy Technology Data Exchange (ETDEWEB)

This document is an executive summary of the colloquium organized by the French syndicate of renewable energies (SER) which took place at the Maison de l'UNESCO in Paris during the national debate on energies organized by the French government in spring 2003. The colloquium was organized around 6 round tables dealing with: the world perspectives and the environmental context of the contribution of renewable energies to the sustainable development (respect of Kyoto protocol commitments, contribution to the security of energy supplies, lack of large scale program of development of decentralized power generation in developing countries, lack of market tools linked with CO{sub 2} emissions, improvement of competitiveness); development of renewable energies in Europe (promotion and sustain in all European countries, obligation of supply and purchase, pricing regulation, European harmonization of practices); renewable electricity and its place in the new ...

International Nuclear Information System (INIS)

Here we report normal-state conductance measurements of three different types of superconducting tunnel junctions that are being used or proposed for quantum computing applications: p-Al/a-AlO/p-Al, e-Re/e-AlO/p-Al, and e-V/e-MgO/p-V, where p stands for polycrystalline, e for epitaxial, and a for amorphous. All three junctions exhibited significant deviations from the parabolic behavior predicted by the WKB approximation models. In the p-Al/a-AlO/p-Al junction, we observed enhancement of tunneling conductances at voltages matching harmonics of Al-O stretching modes. On the other hand, such Al-O vibration modes were missing in the epitaxial e-Re/e-AlO/p-Al junction. This suggests that absence or existence of the Al-O stretching mode might be related to the crystallinity of the AlO tunnel barrier and the interface between the electrode and the barrier. In the e-V/e-MgO/p-V junction, which is one of the candidate systems for future superconducting qubits, we observed ...

International Nuclear Information System (INIS)

The dynamic response of thin liquid storage tanks to earthquakes is a very complicated phenomenon, because it can be highly non linear. Among others, one can meet material and geometric non linearities of the tank shell leading eventually to static or dynamic buckling non linear behavior of anchor bolts, contact non-linearities due to the uplift of the tank base and to the unilateral character of the fluid pressure on the shell and high amplitude fluid oscillations. Moreover, linear or non linear soil structure interaction affects considerably the response of the fluid structure system under consideration. In this paper we focus attention on problems related only to the base uplift and anchors plastification. We study a tank similar to the Hualien project tank, but we neglect the soil structure interaction. The studied tank is representative of medium height to radius ratio ratio tanks with relatively thick bottom plate. The contact is simulated via a simple discrete penalty method in ...

Energy Technology Data Exchange (ETDEWEB)

The adsorption of glycolate anions at sputtered gold thin-film electrodes was studied in perchloric acid solutions by cyclic voltammetry experiments combined with in situ Surface Enhanced Raman Scattering (SERS) and Surface Enhanced Infrared Reflection Absorption Spectroscopy under attenuated total reflection conditions (ATR-SEIRAS). Theoretical harmonic vibrational frequencies and band intensities obtained from B3LYP/LANL2DZ,6-31+G(d) calculations for glycolate species adsorbed on Au clusters with (1 1 1) orientation were used to interpret the experimental spectra. Vibrational data confirm the bidentate bonding of glycolate anions through the oxygen atoms of the carboxylate group, in a bridge configuration with the OCO plane perpendicular to the metal surface. The DFT calculations show no significant effect of the total charge of the metal cluster-adsorbate adduct on the vibrational frequencies of adsorbed glycolate species. The infrared experimental study is ...

Energy Technology Data Exchange (ETDEWEB)

Four 10 MW, highly-stabilized power supply modules have been installed at the National High Magnetic Field Laboratory in Tallahassee, FL, to energize water-cooled, resistive, high-field research magnets. The power supply modules achieve a long term current stability if 10 ppM over a 12 h period with a short term ripple and noise variation of <10 ppM over a time period of one cycle. The power supply modules can operate independently, feeding four separate magnets, or two, three or four modules can operate in parallel. Each power supply module consists of a 12.5 kV vacuum circuit breaker, two three-winding, step-down transformers, a 24-pulse rectifier with interphase reactors, and a passive and an active filter. Two different transformer tap settings allow rated dc supply output voltages of 400 and 500 V. The rated current of a supply module is 17 kA and each supply module has a one-hour overload capability of 20 kA. The isolated output terminals of each power supply module are ...

Energy Technology Data Exchange (ETDEWEB)

A new thin film manufacturing method is established to add a function to glass material surface, as a new material technology which harmonizes with global environment, and is suitable for resource re-utilization and energy conservation. It is intended to develop a leading technology to promote recycling of colored glasses by applying this technical method to colored glasses. Fiscal 1998 has implemented subsequently to fiscal 1997 the following subjects in the three research items composed of a new manufacturing method of functional thin films, application of the functional thin films to colored glasses, and the comprehensive investigative studies: establishment of an industrial manufacturing method for color coating liquid and evaluation of basic characteristics of the colored functional thin films, optimization of element technology for photo-sensitive gel films by means of chemically modifying metallic alkoxide, tests of forming films on glass bottles and plate ...

International Nuclear Information System (INIS)

Illicit trafficking of nuclear and other radioactive material has been an issue of concern since the first seizures in the early 1990s. By the end of 2004 Member States had confirmed 540 cases, while about another 500 remain unconfirmed. Most of the confirmed cases have a criminal dimension, even if they were not for known terrorist purposes. The attacks of September 2001 in the USA dramatically emphasized the requirement for the enhanced control and security of nuclear and other radioactive material. In response to a resolution by the IAEA General Conference in September 2002 the IAEA has adopted an integrated approach to protection against nuclear terrorism. This brings together IAEA activities concerned with the physical protection of nuclear material and nuclear installations, nuclear material accountancy, detection and response to illicit nuclear trafficking, the security and safety of radioactive sources, emergency response measures - including pre-emergency measures in Member ...

Science.gov (United States)

The unsteady aerodynamic forces of a model fruit fly wing in flapping motion were investigated by numerically solving the Navier-Stokes equations. The flapping motion consisted of translation and rotation [the translation velocity (u(t)) varied according to the simple harmonic function (SHF), and the rotation was confined to a short period around stroke reversal]. First, it was shown that for a wing of given geometry with u(t) varying as the SHF, the aerodynamic force coefficients depended only on five non-dimensional parameters, i.e. Reynolds number (Re), stroke amplitude (Phi), mid-stroke angle of attack (alpha(m)), non-dimensional duration of wing rotation (Delta tau(r)) and rotation timing [the mean translation velocity at radius of the second moment of wing area (U), the mean chord length (c) and c/U were used as reference velocity, length and time, respectively]. Next, the force coefficients were investigated for a case in which typical values of these ...