Sample records for loss torque converter

  1. Sensorless Direct Torque Control For Salient Pole PMSM Based on Extended Kalman Filter Fed By AC/DC/AC Converter

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Sensorless Direct Torque Control For Salient ­ Pole PMSM Based on Extended Kalman Filter Fed By AC is proposed. The Direct Torque Control (DTC) technique for PMSM is receiving increasing attention due on the stochastic intromission, in others words, noise. The PMSM is fed by an indirect power electronic converter

  2. Way to reduce arc voltage losses in hybrid thermionic converters

    SciTech Connect (OSTI)

    Tskhakaya, V.K.; Yarygin, V.I.

    1982-03-01T23:59:59.000Z

    Experimental results are reported concerning the output and emission characteristics of the arc and hybrid regimes in a plane-parallel thermionic converter with Pt--Zr--O electrode pair. It is shown that arc voltage losses can be reduced to values below those obtainable in ordinary arc thermionic converters.

  3. Development of an automated efficiency and loss measurement system for high-efficiency power converters

    E-Print Network [OSTI]

    Cheung, Grace M

    2010-01-01T23:59:59.000Z

    When building a high performance power converter system, characterization becomes a significant task in and of itself. This thesis addresses the development of an automated efficiency and loss measurement system for ...

  4. Digital Loss-Minimizing Multi-Mode Synchronous Buck Converter Control Angel V. Peterchev Seth R. Sanders

    E-Print Network [OSTI]

    Sanders, Seth

    transition among the modes. An on-line adaptive algorithm to optimize the SR timing, based on power loss reducing the switching losses. In modern portable applications, minimizing power loss at light load in the controller, or can be obtained on-line by dynamically minimizing the converter power loss via multi

  5. Structural transitions and elasticity from torque measurements on DNA

    E-Print Network [OSTI]

    Bryant, Zev

    wind-up motors and forcetorque converters. Previous investigations of the forceextension behaviour processes such as replication and transcription. Measurements of force and extension on single molecules-induced transitions in DNA structure6,7 , and a theoretical forcetorque phase diagram has been proposed that explains

  6. Realizing Torque Controllers for Underactuated Bipedal Walking Using the Ideal Model Resolved Motion Method

    E-Print Network [OSTI]

    Cousineau, Eric Andrew

    2014-12-16T23:59:59.000Z

    ), which is a simple method to convert ideal torque controllers to PD controllers to implement on hardware. Walking was first achieved using the proven method of the hybrid zero dynamics (HZD) reconstruction, followed by the Input-Output Feedback...

  7. Beam converter

    DOE Patents [OSTI]

    Poulsen, Peter

    2003-05-06T23:59:59.000Z

    A converter and method for converting electron energy to irradiative energy comprising foam and/or foil. Foam and foil optionally comprise a high-Z material, such as, but not limited to, tantalum.

  8. Reconstructing the intermittent dynamics of the torque in wind turbines

    E-Print Network [OSTI]

    Lind, Pedro G; Peinke, Joachim

    2014-01-01T23:59:59.000Z

    We apply a framework introduced in the late nineties to analyze load measurements in off-shore wind energy converters (WEC). The framework is borrowed from statistical physics and properly adapted to the analysis of multivariate data comprising wind velocity, power production and torque measurements, taken at one single WEC. In particular, we assume that wind statistics drives the fluctuations of the torque produced in the wind turbine and show how to extract an evolution equation of the Langevin type for the torque driven by the wind velocity. It is known that the intermittent nature of the atmosphere, i.e. of the wind field, is transferred to the power production of a wind energy converter and consequently to the shaft torque. We show that the derived stochastic differential equation quantifies the dynamical coupling of the measured fluctuating properties as well as it reproduces the intermittency observed in the data. Finally, we discuss our approach in the light of turbine monitoring, a particular importa...

  9. Cell modulated DC/DC converter

    E-Print Network [OSTI]

    Warren, James Raymond, III

    2005-01-01T23:59:59.000Z

    A very high frequency converter roughly based on a class E topology is investigated for replacing a conventional boost converter circuit. The loss mechanisms in class E inverters are characterized, and metrics are developed ...

  10. automotive torque converter: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    at Ford Motor Company. Currently, Ford has Garlan, David 123 Analysis of Automotive Turbocharger Nonlinear Response Including Bifurcations. Open Access Theses and Dissertations...

  11. Quick torque coupling

    DOE Patents [OSTI]

    Luft, Peter A. (El Cerrito, CA)

    2009-05-12T23:59:59.000Z

    A coupling for mechanically connecting modular tubular struts of a positioning apparatus or space frame, comprising a pair of toothed rings (10, 12) attached to separate strut members (16), the teeth (18, 20) of the primary rings (10, 12) mechanically interlocking in both an axial and circumferential manner, and a third part comprising a sliding, toothed collar (14) the teeth (22) of which interlock the teeth (18, 20) of the primary rings (10, 12), preventing them from disengaging, and completely locking the assembly together. A secondary mechanism provides a nesting force for the collar, and/or retains it. The coupling is self-contained and requires no external tools for installation, and can be assembled with gloved hands in demanding environments. No gauging or measured torque is required for assembly. The assembly can easily be visually inspected to determine a "go" or "no-go" status. The coupling is compact and relatively light-weight. Because of it's triply interlocking teeth, the connection is rigid. The connection does not primarily rely on clamps, springs or friction based fasteners, and is therefore reliable in fail-safe applications.

  12. Proton transport and torque generation in rotary biomotors

    E-Print Network [OSTI]

    A. Yu. Smirnov; S. Savel'ev; L. G. Mourokh; Franco Nori

    2008-05-29T23:59:59.000Z

    We analyze the dynamics of rotary biomotors within a simple nano-electromechanical model, consisting of a stator part and a ring-shaped rotor having twelve proton-binding sites. This model is closely related to the membrane-embedded F$_0$ motor of adenosine triphosphate (ATP) synthase, which converts the energy of the transmembrane electrochemical gradient of protons into mechanical motion of the rotor. It is shown that the Coulomb coupling between the negative charge of the empty rotor site and the positive stator charge, located near the periplasmic proton-conducting channel (proton source), plays a dominant role in the torque-generating process. When approaching the source outlet, the rotor site has a proton energy level higher than the energy level of the site, located near the cytoplasmic channel (proton drain). In the first stage of this torque-generating process, the energy of the electrochemical potential is converted into potential energy of the proton-binding sites on the rotor. Afterwards, the tangential component of the Coulomb force produces a mechanical torque. We demonstrate that, at low temperatures, the loaded motor works in the shuttling regime where the energy of the electrochemical potential is consumed without producing any unidirectional rotation. The motor switches to the torque-generating regime at high temperatures, when the Brownian ratchet mechanism turns on. In the presence of a significant external torque, created by ATP hydrolysis, the system operates as a proton pump, which translocates protons against the transmembrane potential gradient. Here we focus on the F$_0$ motor, even though our analysis is applicable to the bacterial flagellar motor.

  13. Thermionic converter

    DOE Patents [OSTI]

    Fitzpatrick, G.O.

    1987-05-19T23:59:59.000Z

    A thermionic converter is set forth which includes an envelope having an electron collector structure attached adjacent to a wall. An electron emitter structure is positioned adjacent the collector structure and spaced apart from opposite wall. The emitter and collector structures are in a common chamber. The emitter structure is heated substantially only by thermal radiation. Very small interelectrode gaps can be maintained utilizing the thermionic converter whereby increased efficiency results. 10 figs.

  14. Thermionic converter

    DOE Patents [OSTI]

    Fitzpatrick, Gary O. (Livermore, CA)

    1987-05-19T23:59:59.000Z

    A thermionic converter (10) is set forth which includes an envelope (12) having an electron collector structure (22) attached adjacent to a wall (16). An electron emitter structure (24) is positioned adjacent the collector structure (22) and spaced apart from opposite wall (14). The emitter (24) and collector (22) structures are in a common chamber (20). The emitter structure (24) is heated substantially only by thermal radiation. Very small interelectrode gaps (28) can be maintained utilizing the thermionic converter (10) whereby increased efficiency results.

  15. Functional Keldysh theory of spin torques

    E-Print Network [OSTI]

    Duine, R. A.; Nunez, A. S.; Sinova, Jairo; MacDonald, A. H.

    2007-01-01T23:59:59.000Z

    stochastic Landau-Lifschitz-Gilbert equation with spin-transfer torques. We calculate the Gilbert damping parameter alpha and the nonadiabatic spin transfer torque parameter beta for a model ferromagnet. We find that beta not equal alpha, in agreement...

  16. Thermionic converter

    SciTech Connect (OSTI)

    Fitzpatrick, G.O.

    1987-05-19T23:59:59.000Z

    A thermionic converter is described comprising: an envelope having first and second walls spaced apart from one another. The envelope defines an enclosed chamber; an electron collector structure attached adjacent to the second wall; an electron emitter structure, located adjacent the collector structure and between the collector structure and the first wall. At least a respective one of the collector structure and the emitter structure comprise elements, each of the elements along with a respective other of the collector structure and the emitter structure defining interelectrode gaps at least when the emitter structure is above a selected temperature. The emitter structure is spaced a distance away from the first wall and is positioned to receive substantially only thermal radiation.

  17. Torque limited drive for manual valves

    DOE Patents [OSTI]

    Elliott, Philip G. (Metropolis, IL); Underwood, Daniel E. (Paducah, KY)

    1989-01-01T23:59:59.000Z

    The present invention is directed to a torque-limiting handwheel device for preventing manual valves from being damaged due to the application of excessive torque during the opening or closing operation of the valves. Torque can only be applied when ridges in the handwheel assembly engage in channels machined in the face of the baseplate. The amount of torque required for disengagement of the ridges from the channels is determined by the force exerted by various Bellville springs and the inclination of the side faces of the channels.

  18. An evaluation of a parallel-resonant current-source converter for an electrothermal thruster

    E-Print Network [OSTI]

    Tchamdjou, Aristide-Marie

    1996-01-01T23:59:59.000Z

    The Parallel-Resonant Current-Source Converter promises highly efficient DCDC power conversion. It uses zero-voltage switching to reduce the losses and improve the converter efficiency. The Parallel-Resonant Current-Source Converter has been...

  19. An evaluation of a parallel-resonant current-source converter for an electrothermal thruster

    E-Print Network [OSTI]

    Tchamdjou, Aristide-Marie

    1996-01-01T23:59:59.000Z

    The Parallel-Resonant Current-Source Converter promises highly efficient DCDC power conversion. It uses zero-voltage switching to reduce the losses and improve the converter efficiency. The Parallel-Resonant Current-Source Converter has been...

  20. Self-oscillation in spin torque oscillator stabilized by field-like torque

    SciTech Connect (OSTI)

    Taniguchi, Tomohiro; Tsunegi, Sumito; Kubota, Hitoshi; Imamura, Hiroshi [National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba 305-8568 (Japan)

    2014-04-14T23:59:59.000Z

    The effect of the field-like torque on the self-oscillation of the magnetization in spin torque oscillator with a perpendicularly magnetized free layer was studied theoretically. A stable self-oscillation at zero field is excited for negative ? while the magnetization dynamics stops for ??=?0 or ??>?0, where ? is the ratio between the spin torque and the field-like torque. The reason why only the negative ? induces the self-oscillation was explained from the view point of the energy balance between the spin torque and the damping. The oscillation power and frequency for various ? were also studied by numerical simulation.

  1. RADIOACTIVE MATERIAL PACKAGING TORQUE REQUIREMENTS COMPLIANCE

    SciTech Connect (OSTI)

    Watkins, R.; Leduc, D.

    2011-03-24T23:59:59.000Z

    Shipping containers used to transport radioactive material (RAM) in commerce employ a variety of closure mechanisms. Often, these closure mechanisms require a specific amount of torque be applied to a bolt, nut or other threaded fastener. It is important that the required preload is achieved so that the package testing and analysis is not invalidated for the purpose of protecting the public. Torque compliance is a means of ensuring closure preload, is a major factor in accomplishing the package functions of confinement/containment, sub-criticality, and shielding. This paper will address the importance of applying proper torque to package closures, discuss torque value nomenclature, and present one methodology to ensure torque compliance is achieved.

  2. Hybrid switch for resonant power converters

    DOE Patents [OSTI]

    Lai, Jih-Sheng; Yu, Wensong

    2014-09-09T23:59:59.000Z

    A hybrid switch comprising two semiconductor switches connected in parallel but having different voltage drop characteristics as a function of current facilitates attainment of zero voltage switching and reduces conduction losses to complement reduction of switching losses achieved through zero voltage switching in power converters such as high-current inverters.

  3. Combustion converter design evolution

    SciTech Connect (OSTI)

    Goodale, D.B.; Miskolczy, G.

    1984-08-01T23:59:59.000Z

    The early thermionic converters used hemispherical one-inch-diameter hot shells. They were extensively tested in a natural gas, high-temperature furnace. A converter was life tested for 12,500 hours at emitter temperatures above 1700 K. Two-inch diameter converters with both hemispherical and torispherical shapes were developed next. These converters have been tested in both natural gas-, oil-, and coal-oil slurry-fired environments. A prototype converter for cogeneration applications was also developed using this emitter configuration. A six converter module of cogeneration converters has been constructed.

  4. Full bridge converter Transformers and isolated converters

    E-Print Network [OSTI]

    Knobloch,Jrgen

    Full bridge converter Transformers and isolated converters Most DC power supplies have the following requirements: 1. Regulated output voltage Solved by a large capacitor at the output, and feedback control. 2. High power factor PFC - discussed previously. 3. Isolation 4. Multiple outputs Isolated

  5. Torque limit of PM motors for field-weakening region operation

    DOE Patents [OSTI]

    Royak, Semyon (Beachwood, OH); Harbaugh, Mark M. (Richfield, OH)

    2012-02-14T23:59:59.000Z

    The invention includes a motor controller and technique for controlling a permanent magnet motor. In accordance with one aspect of the present technique, a permanent magnet motor is controlled by receiving a torque command, determining a physical torque limit based on a stator frequency, determining a theoretical torque limit based on a maximum available voltage and motor inductance ratio, and limiting the torque command to the smaller of the physical torque limit and the theoretical torque limit. Receiving the torque command may include normalizing the torque command to obtain a normalized torque command, determining the physical torque limit may include determining a normalized physical torque limit, determining a theoretical torque limit may include determining a normalized theoretical torque limit, and limiting the torque command may include limiting the normalized torque command to the smaller of the normalized physical torque limit and the normalized theoretical torque limit.

  6. Interleaved power converter

    DOE Patents [OSTI]

    Zhu, Lizhi (Canton, MI)

    2007-11-13T23:59:59.000Z

    A power converter architecture interleaves full bridge converters to alleviate thermal management problems in high current applications, and may, for example, double the output power capability while reducing parts count and costs. For example, one phase of a three phase inverter is shared between two transformers, which provide power to a rectifier such as a current doubler rectifier to provide two full bridge DC/DC converters with three rather than four high voltage inverter legs.

  7. ITER convertible blanket evaluation

    SciTech Connect (OSTI)

    Wong, C.P.C.; Cheng, E.

    1995-09-01T23:59:59.000Z

    Proposed International Thermonuclear Experimental Reactor (ITER) convertible blankets were reviewed. Key design difficulties were identified. A new particle filter concept is introduced and key performance parameters estimated. Results show that this particle filter concept can satisfy all of the convertible blanket design requirements except the generic issue of Be blanket lifetime. If the convertible blanket is an acceptable approach for ITER operation, this particle filter option should be a strong candidate.

  8. Universal thermochemical energy converter

    DOE Patents [OSTI]

    Labinov, Solomon Davidovich (Oak Ridge, TN); Sand, James R. (Oak Ridge, TN); Conklin, James C. (Knoxville, TN); VanCoevering, James (Oak Ridge, TN); Courville, George E. (Oak Ridge, TN)

    2001-01-01T23:59:59.000Z

    Disclosed are methods and apparatus for a thermochemical closed cycle employing a polyatomic, chemically active working fluid for converting heat energy into useful work.

  9. Microminiature thermionic converters

    DOE Patents [OSTI]

    King, Donald B. (Albuquerque, NM); Sadwick, Laurence P. (Salt Lake City, UT); Wernsman, Bernard R. (Clairton, PA)

    2001-09-25T23:59:59.000Z

    Microminiature thermionic converts (MTCs) having high energy-conversion efficiencies and variable operating temperatures. Methods of manufacturing those converters using semiconductor integrated circuit fabrication and micromachine manufacturing techniques are also disclosed. The MTCs of the invention incorporate cathode to anode spacing of about 1 micron or less and use cathode and anode materials having work functions ranging from about 1 eV to about 3 eV. Existing prior art thermionic converter technology has energy conversion efficiencies ranging from 5-15%. The MTCs of the present invention have maximum efficiencies of just under 30%, and thousands of the devices can be fabricated at modest costs.

  10. Numerical Estimation of Frictional Torques with Rate and State Friction

    E-Print Network [OSTI]

    Arun K. Singh; T. N. Singh

    2015-01-20T23:59:59.000Z

    In this paper, numerical estimation of frictional torques is carried out of a rotary elastic disc on a hard and rough surface under different rotating conditions. A one dimensional spring- mass rotary system is numerically solved under the quasistatic condition with the rate and state dependent friction model. It is established that torque of frictional strength as well as torque of steady dynamic stress increases with radius and found to be maximum at the periphery of the disc. Torque corresponding to frictional strength estimated using the analytical solution matches closely with the simulation only in the case of high stiffness of the connecting spring. In steady relaxation simulation, a steadily rotating disc is suddenly stopped and relaxational angular velocity and corresponding frictional torque decreases with both steady angular velocity and stiffness of the connecting spring in the velocity strengthening regime. In velocity weakening regime, in contrast, torque of relaxation stress deceases but relaxation velocity increases. The reason for the contradiction is explained.

  11. The optical torque on small bi-isotropic particles

    E-Print Network [OSTI]

    Nieto-Vesperinas, Manuel

    2015-01-01T23:59:59.000Z

    Most previous theoretical studies on the optical torque exerted by light on dipolar particles are incomplete. Here we establish the equations for the time-averaged optical torque on dipolar bi-isotropic particles. Due to the interference of scattered fields, it has a term additional to that commonly employed in theory and experiments. Its consequences for conservation of energy, angular momentum, and effects like negative torques, are discussed.

  12. ankle torque steadiness: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    balance for people with amputation. We designed a tethered ankle Collins, Steven H. 4 Design of Two Lightweight, High-Bandwidth Torque-Controlled Ankle Exoskeletons Engineering...

  13. NovaTorque | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are beingZealand Jump to: navigation, searchOfRoseConcerns Jumpsource History ViewTexas:Notrees 1B (GENovaTorque Jump

  14. Vector generator scan converter

    DOE Patents [OSTI]

    Moore, James M. (Livermore, CA); Leighton, James F. (Livermore, CA)

    1990-01-01T23:59:59.000Z

    High printing speeds for graphics data are achieved with a laser printer by transmitting compressed graphics data from a main processor over an I/O (input/output) channel to a vector generator scan converter which reconstructs a full graphics image for input to the laser printer through a raster data input port. The vector generator scan converter includes a microprocessor with associated microcode memory containing a microcode instruction set, a working memory for storing compressed data, vector generator hardward for drawing a full graphic image from vector parameters calculated by the microprocessor, image buffer memory for storing the reconstructed graphics image and an output scanner for reading the graphics image data and inputting the data to the printer. The vector generator scan converter eliminates the bottleneck created by the I/O channel for transmitting graphics data from the main processor to the laser printer, and increases printer speed up to thirty fold.

  15. Vector generator scan converter

    DOE Patents [OSTI]

    Moore, J.M.; Leighton, J.F.

    1988-02-05T23:59:59.000Z

    High printing speeds for graphics data are achieved with a laser printer by transmitting compressed graphics data from a main processor over an I/O channel to a vector generator scan converter which reconstructs a full graphics image for input to the laser printer through a raster data input port. The vector generator scan converter includes a microprocessor with associated microcode memory containing a microcode instruction set, a working memory for storing compressed data, vector generator hardware for drawing a full graphic image from vector parameters calculated by the microprocessor, image buffer memory for storing the reconstructed graphics image and an output scanner for reading the graphics image data and inputting the data to the printer. The vector generator scan converter eliminates the bottleneck created by the I/O channel for transmitting graphics data from the main processor to the laser printer, and increases printer speed up to thirty fold. 7 figs.

  16. TorqueSpeed Relationships of Na+ -driven Chimeric

    E-Print Network [OSTI]

    Berry, Richard

    , H+ in Escherichia coli and Na+ in marine Vibrio species, driven by an inward-directed electrochemiTorqueSpeed Relationships of Na+ -driven Chimeric Flagellar Motors in Escherichia coli Yuichi in Escherichia coli promises to reveal the mechanism of the motor in unprecedented detail. We measured torque

  17. Analysis and design of a saturable reactor assisted soft-switching full-bridge dc-dc converter

    SciTech Connect (OSTI)

    Hamada, Satoshi (Sansha Electric Manufacturing Co., Ltd., Osaka (Japan)); Nakaoka, Mutsuo (Kobe Univ. (Japan). Dept. of Electrical and Electronics Engineering)

    1994-05-01T23:59:59.000Z

    Analysis and design considerations for a saturable reactor assisted soft-switching full-bridge dc-dc converter are presented. The converter has advantages such as low switching losses with no substantial increase in conduction losses, wide load range, and constant frequency operation. To show how to utilize the analysis results, a 350-W, 500-kHz converter is chosen as a design example. The results are verified experimentally on a prototype converter.

  18. Radiative torques on interstellar grains; 1, superthermal spinup

    E-Print Network [OSTI]

    Draine, B T; Weingartner, Joseph C

    1996-01-01T23:59:59.000Z

    Irregular dust grains are subject to radiative torques when irradiated by interstellar starlight. It is shown how these radiative torques may be calculated using the discrete dipole approximation. Calculations are carried out for one irregular grain geometry, and three different grain sizes. It is shown that radiative torques can play an important dynamical role in spinup of interstellar dust grains, resulting in rotation rates which may exceed even those expected from H_2 formation on the grain surface. Because the radiative torque on an interstellar grain is determined by the overall grain geometry rather than merely the state of the grain surface, the resulting superthermal rotation is expected to be long-lived. By itself, long-lived superthermal rotation would permit grain alignment by normal paramagnetic dissipation on the "Davis-Greenstein" timescale. However, radiative torques arising from anisotropy of the starlight background can act directly to alter the grain alignment on much shorter timescales, a...

  19. DC systems with transformerless converters

    SciTech Connect (OSTI)

    Vithayathil, J.J.; Mittlestadt, W. [Bonneville Power Administration, Portland, OR (United States)] [Bonneville Power Administration, Portland, OR (United States); Bjoerklund, P.E. [ABB Power Systems AB, Ludvika (Sweden)] [ABB Power Systems AB, Ludvika (Sweden)

    1995-07-01T23:59:59.000Z

    A technical and economic feasibility study of HVDC systems without converter transformers is presented. The presentation includes proposed solutions to the drawback related to the absence of galvanic separation between the ac and dc systems, if the converter transformers are eliminated. The results show that HVDC systems without converter transformers are both technically and economically feasible. The cost savings can be substantial.

  20. Lindblad resonance torques in relativistic discs: I. Basic equations

    E-Print Network [OSTI]

    Christopher M. Hirata

    2011-03-01T23:59:59.000Z

    Lindblad resonances have been suggested as an important mechanism for angular momentum transport and heating in discs in binary black hole systems. We present the basic equations for the torque and heating rate for relativistic thin discs subjected to a perturbation. The Lindblad resonance torque is written explicitly in terms of metric perturbations for an equatorial disc in a general axisymmetric, time-stationary spacetime with a plane of symmetry. We show that the resulting torque formula is gauge-invariant. Computations for the Schwarzschild and Kerr spacetimes are presented in the companion paper.

  1. Solar thermionic energy converter experiment

    SciTech Connect (OSTI)

    Goodale, D.; Lieb, D.; Neale, D.

    1982-08-01T23:59:59.000Z

    A one-inch CVD converter was solar tested in a central receiver heliostat array at the Advanced Components Test Facility at the Georgia Institute of Technology. The test examined heat flux cycling control of the operating point and mounting arrangements. The converter was mounted directly in the solar image with no cavity. The input heat flux was 40-60 W/cm/sup 2/. The converter performance was comparable to combustion measurements made on the same diode. Thermal cycling caused no problems with converter operation. The converter showed no degradation after the test.

  2. Thermionic electric converter

    SciTech Connect (OSTI)

    Davis, E.D.

    1981-12-01T23:59:59.000Z

    A thermionic electric converter is disclosed wherein an externally located heat source causes electrons to be boiled off an electron emissive surface interiorly positioned on one end wall of an evacuated cylindrical chamber. The electrons are electrically focused and accelerated through the interior of an air core induction coil located within a transverse magnetic field, and subsequently are collected on the other end wall of the chamber functioning as a collecting plate. The emf generated in the induction coil by action of the transiting electron stream interacting with the transverse magnetic field is applied to an external circuit to perform work, thereby implementing a direct heat energy to electrical energy conversion.

  3. Cycloidal Wave Energy Converter

    SciTech Connect (OSTI)

    Stefan G. Siegel, Ph.D.

    2012-11-30T23:59:59.000Z

    This program allowed further advancing the development of a novel type of wave energy converter, a Cycloidal Wave Energy Converter or CycWEC. A CycWEC consists of one or more hydrofoils rotating around a central shaft, and operates fully submerged beneath the water surface. It operates under feedback control sensing the incoming waves, and converts wave power to shaft power directly without any intermediate power take off system. Previous research consisting of numerical simulations and two dimensional small 1:300 scale wave flume experiments had indicated wave cancellation efficiencies beyond 95%. The present work was centered on construction and testing of a 1:10 scale model and conducting two testing campaigns in a three dimensional wave basin. These experiments allowed for the first time for direct measurement of electrical power generated as well as the interaction of the CycWEC in a three dimensional environment. The Atargis team successfully conducted two testing campaigns at the Texas A&M Offshore Technology Research Center and was able to demonstrate electricity generation. In addition, three dimensional wave diffraction results show the ability to achieve wave focusing, thus increasing the amount of wave power that can be extracted beyond what was expected from earlier two dimensional investigations. Numerical results showed wave cancellation efficiencies for irregular waves to be on par with results for regular waves over a wide range of wave lengths. Using the results from previous simulations and experiments a full scale prototype was designed and its performance in a North Atlantic wave climate of average 30kW/m of wave crest was estimated. A full scale WEC with a blade span of 150m will deliver a design power of 5MW at an estimated levelized cost of energy (LCOE) in the range of 10-17 US cents per kWh. Based on the new results achieved in the 1:10 scale experiments these estimates appear conservative and the likely performance at full scale will exceed this initial performance estimates. In advancing the Technology Readiness Level (TRL) of this type of wave energy converter from 3 to 4, we find the CycWEC to exceed our initial estimates in terms of hydrodynamic performance. Once fully developed and optimized, it has the potential to not just outperform all other WEC technologies, but to also deliver power at a lower LCOE than competing conventional renewables like wind and solar. Given the large wave power resource both domestically and internationally, this technology has the potential to lead to a large improvement in our ability to produce clean electricity at affordable cost.

  4. Radiative Torques on Interstellar Grains; 2, Grain Alignment

    E-Print Network [OSTI]

    Draine, B T; Weingartner, Joseph C.

    1996-01-01T23:59:59.000Z

    Radiative torques on irregular dust grains, in addition to producing superthermal rotation, play a direct dynamical role in the alignment of interstellar dust with the local magnetic field. The equations governing the orientation of spinning, precessing grains are derived; H_2 formation torques and paramagnetic dissipation are included in the dynamics. Stationary solutions (constant alignment angle and spin rate) are found; these solutions may be stable ("attractors") or unstable ("repellors"). The equations of motion are numerically integrated for three exemplary irregular grain geometries, exposed to anisotropic radiation with the spectrum of interstellar starlight. The resulting "trajectory maps" are classified as "noncyclic", "semicyclic", or "cyclic", with examples of each given. We find that radiative torques result in rapid grain alignment, even in the absence of paramagnetic dissipation. It appears that radiative torques due to starlight can account for the observed alignment of interstellar grains wi...

  5. affects torque production: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Sciences (arXiv) Summary: We demonstrate that the synchronization of an array of electrically coupled spin torque nano-oscillators (STNO) modelled by Landau-Lifshitz-Gilbert-Slo...

  6. Mechanics of torque generation in the bacterial flagellar motor

    E-Print Network [OSTI]

    Mandadapu, Kranthi K; Berry, Richard M; Oster, George

    2015-01-01T23:59:59.000Z

    The bacterial flagellar motor (BFM) is responsible for driving bacterial locomotion and chemotaxis, fundamental processes in pathogenesis and biofilm formation. In the BFM, torque is generated at the interface between transmembrane proteins (stators) and a rotor. It is well-established that the passage of ions down a transmembrane gradient through the stator complex provides the energy needed for torque generation. However, the physics involved in this energy conversion remain poorly understood. Here we propose a mechanically specific model for torque generation in the BFM. In particular, we identify two fundamental forces involved in torque generation: electrostatic and steric. We propose that electrostatic forces serve to position the stator, while steric forces comprise the actual 'power stroke'. Specifically, we predict that ion-induced conformational changes about a proline 'hinge' residue in an $\\alpha$-helix of the stator are directly responsible for generating the power stroke. Our model predictions f...

  7. Production Experiences with the Cray-Enabled TORQUE Resource Manager

    SciTech Connect (OSTI)

    Ezell, Matthew A [ORNL] [ORNL; Maxwell, Don E [ORNL] [ORNL; Beer, David [Adaptive Computing] [Adaptive Computing

    2013-01-01T23:59:59.000Z

    High performance computing resources utilize batch systems to manage the user workload. Cray systems are uniquely different from typical clusters due to Cray s Application Level Placement Scheduler (ALPS). ALPS manages binary transfer, job launch and monitoring, and error handling. Batch systems require special support to integrate with ALPS using an XML protocol called BASIL. Previous versions of Adaptive Computing s TORQUE and Moab batch suite integrated with ALPS from within Moab, using PERL scripts to interface with BASIL. This would occasionally lead to problems when all the components would become unsynchronized. Version 4.1 of the TORQUE Resource Manager introduced new features that allow it to directly integrate with ALPS using BASIL. This paper describes production experiences at Oak Ridge National Laboratory using the new TORQUE software versions, as well as ongoing and future work to improve TORQUE.

  8. Bidirectional buck boost converter

    DOE Patents [OSTI]

    Esser, A.A.M.

    1998-03-31T23:59:59.000Z

    A bidirectional buck boost converter and method of operating the same allows regulation of power flow between first and second voltage sources in which the voltage level at each source is subject to change and power flow is independent of relative voltage levels. In one embodiment, the converter is designed for hard switching while another embodiment implements soft switching of the switching devices. In both embodiments, first and second switching devices are serially coupled between a relatively positive terminal and a relatively negative terminal of a first voltage source with third and fourth switching devices serially coupled between a relatively positive terminal and a relatively negative terminal of a second voltage source. A free-wheeling diode is coupled, respectively, in parallel opposition with respective ones of the switching devices. An inductor is coupled between a junction of the first and second switching devices and a junction of the third and fourth switching devices. Gating pulses supplied by a gating circuit selectively enable operation of the switching devices for transferring power between the voltage sources. In the second embodiment, each switching device is shunted by a capacitor and the switching devices are operated when voltage across the device is substantially zero. 20 figs.

  9. Bidirectional buck boost converter

    DOE Patents [OSTI]

    Esser, Albert Andreas Maria (Niskayuna, NY)

    1998-03-31T23:59:59.000Z

    A bidirectional buck boost converter and method of operating the same allows regulation of power flow between first and second voltage sources in which the voltage level at each source is subject to change and power flow is independent of relative voltage levels. In one embodiment, the converter is designed for hard switching while another embodiment implements soft switching of the switching devices. In both embodiments, first and second switching devices are serially coupled between a relatively positive terminal and a relatively negative terminal of a first voltage source with third and fourth switching devices serially coupled between a relatively positive terminal and a relatively negative terminal of a second voltage source. A free-wheeling diode is coupled, respectively, in parallel opposition with respective ones of the switching devices. An inductor is coupled between a junction of the first and second switching devices and a junction of the third and fourth switching devices. Gating pulses supplied by a gating circuit selectively enable operation of the switching devices for transferring power between the voltage sources. In the second embodiment, each switching device is shunted by a capacitor and the switching devices are operated when voltage across the device is substantially zero.

  10. Radiative Torques on Interstellar Grains: I. Superthermal Spinup

    E-Print Network [OSTI]

    B. T. Draine; Joseph C. Weingartner

    1996-05-09T23:59:59.000Z

    Irregular dust grains are subject to radiative torques when irradiated by interstellar starlight. It is shown how these radiative torques may be calculated using the discrete dipole approximation. Calculations are carried out for one irregular grain geometry, and three different grain sizes. It is shown that radiative torques can play an important dynamical role in spinup of interstellar dust grains, resulting in rotation rates which may exceed even those expected from H_2 formation on the grain surface. Because the radiative torque on an interstellar grain is determined by the overall grain geometry rather than merely the state of the grain surface, the resulting superthermal rotation is expected to be long-lived. By itself, long-lived superthermal rotation would permit grain alignment by normal paramagnetic dissipation on the "Davis-Greenstein" timescale. However, radiative torques arising from anisotropy of the starlight background can act directly to alter the grain alignment on much shorter timescales, and are therefore central to the process of interstellar grain alignment. Radiative torques depend strongly on the grain size, measured by a_eff, the radius of a sphere of equal volume. In diffuse clouds, radiative torques dominate the torques due to H2 formation for a_eff=0.2micron grains, but are relatively unimportant for a_eff0.1 micron grains in diffuse clouds are aligned, while there is little alignment of a_eff superthermal rotation within quiescent dark clouds, but can be very effective in star-forming regions such as the M17 molecular cloud.

  11. A 660MHz ZVS DC-DC Converter Using Gate-Driver Charge-Recycling in 0.18m

    E-Print Network [OSTI]

    Lemieux, Guy

    allows full integration of these power supplies. To compensate for the switching power loss under high switch mode power converters, zero voltage switching (ZVS) operation is used to reduce dynamic power loss

  12. Mechanics of torque generation in the bacterial flagellar motor

    E-Print Network [OSTI]

    Kranthi K. Mandadapu; Jasmine A. Nirody; Richard M. Berry; George Oster

    2015-01-13T23:59:59.000Z

    The bacterial flagellar motor (BFM) is responsible for driving bacterial locomotion and chemotaxis, fundamental processes in pathogenesis and biofilm formation. In the BFM, torque is generated at the interface between transmembrane proteins (stators) and a rotor. It is well-established that the passage of ions down a transmembrane gradient through the stator complex provides the energy needed for torque generation. However, the physics involved in this energy conversion remain poorly understood. Here we propose a mechanically specific model for torque generation in the BFM. In particular, we identify two fundamental forces involved in torque generation: electrostatic and steric. We propose that electrostatic forces serve to position the stator, while steric forces comprise the actual 'power stroke'. Specifically, we predict that ion-induced conformational changes about a proline 'hinge' residue in an $\\alpha$-helix of the stator are directly responsible for generating the power stroke. Our model predictions fit well with recent experiments on a single-stator motor. Furthermore, we propose several experiments to elucidate the torque-speed relationship in motors where the number of stators may not be constant. The proposed model provides a mechanical explanation for several fundamental features of the flagellar motor, including: torque-speed and speed-ion motive force relationships, backstepping, variation in step sizes, and the puzzle of swarming experiments.

  13. A Virtual DSP System for Design Instruction of Power Converters AA.. KKeeyyhhaannii aanndd MM.. NN.. MMaarrwwaallii GGeerraalldd BBaauummggaarrttnneerr

    E-Print Network [OSTI]

    Baumgartner, Gerald

    as a case study for the development of the testbed. The resonant power converters provide efficient electric `hard' switching power converters, a resonant converter utilizes a controlled series or parallel LC substantially reduce the switching losses occurred in the power transfer process Despite their attractiveness

  14. Converting Biomass to Products

    SciTech Connect (OSTI)

    Graybeal, Judith W.

    2006-06-01T23:59:59.000Z

    For nearly 30 years, PNNL has been developing and applying novel thermal, chemical and biological processes to convert biomass to industrial and consumer products, fuels and energy. Honors for technologies resulting from this research include the Presidential Green Chemistry Award and several Federal Laboratory Consortium and R&D 100 Awards. PNNLs research and development activities address the complete processing scheme, from feedstock pretreatment to purified product recovery. The laboratory applies fundamental science and advanced engineering capabilities to biomass conversion and processing to ensure effective recovery of optimal value from biomass; carbohydrate polymer systems to maximize energy efficiencies; and micro-technology systems for separation and conversion processes. For example, bioproducts researchers in the laboratorys Institute for Interfacial Catalysis develop and demonstrate the utility of new catalyst formulations for production of bio-based chemicals. This article describes a sampling of current and recent catalysis projects for biomass conversion.

  15. Self-powered microthermionic converter

    DOE Patents [OSTI]

    Marshall, Albert C.; King, Donald B.; Zavadil, Kevin R.; Kravitz, Stanley H.; Tigges, Chris P.; Vawter, Gregory A.

    2004-08-10T23:59:59.000Z

    A self-powered microthermionic converter having an internal thermal power source integrated into the microthermionic converter. These converters can have high energy-conversion efficiencies over a range of operating temperatures. Microengineering techniques are used to manufacture the converter. The utilization of an internal thermal power source increases potential for mobility and incorporation into small devices. High energy efficiency is obtained by utilization of micron-scale interelectrode gap spacing. Alpha-particle emitting radioisotopes can be used for the internal thermal power source, such as curium and polonium isotopes.

  16. Thyristor converter simulation and analysis

    SciTech Connect (OSTI)

    Zhang, S.Y.

    1991-01-01T23:59:59.000Z

    In this paper we present a simulation on thyristor converters. The simulation features nonlinearity, non-uniform firing, and the commutations. Several applications such as a current regulation, a converter frequency characteristics analysis, and a power line disturbance analysis will be presented. 4 refs., 4 figs.

  17. Heat engine and electric motor torque distribution strategy for a hybrid electric vehicle

    DOE Patents [OSTI]

    Boberg, Evan S. (Hazel Park, MI); Gebby, Brian P. (Hazel Park, MI)

    1999-09-28T23:59:59.000Z

    A method is provided for controlling a power train system for a hybrid electric vehicle. The method includes a torque distribution strategy for controlling the engine and the electric motor. The engine and motor commands are determined based upon the accelerator position, the battery state of charge and the amount of engine and motor torque available. The amount of torque requested for the engine is restricted by a limited rate of rise in order to reduce the emissions from the engine. The limited engine torque is supplemented by motor torque in order to meet a torque request determined based upon the accelerator position.

  18. Influence of control strategy on the global efficiency of a Direct Wave Energy Converter with

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    Influence of control strategy on the global efficiency of a Direct Wave Energy Converter, France Abstract--The choice of control strategy for Direct Wave Energy Converters (DWEC) is often a simple loss model in order to design a better control strategy. Keywords--Wave energy conversion; Point

  19. Ac-Ac Dual Active Bridge Converter for Solid State Transformer

    E-Print Network [OSTI]

    Kimball, Jonathan W.

    flow. The advantages of direct ac-ac conversion include fewer power conversion stages and minimized single-stage direct ac-ac power conversion to an SST. Fewer conversion stages reduce conduction loss) converter in direct ac-ac power conversion. Like a DAB converter as dc-dc power supply in [5] and [6

  20. Torques on Spheroidal Silicate Grains Exposed to Anisotropic Interstellar Radiation Fields

    E-Print Network [OSTI]

    Joseph C. Weingartner; Margaret E. Jordan

    2007-09-26T23:59:59.000Z

    Radiative torques, due to the absorption and scattering of starlight, are thought to play a major role in the alignment of grains with the interstellar magnetic field. The absorption of radiation also gives rise to recoil torques, associated with the photoelectric effect and photodesorption. The recoil torques are much more difficult to model and compute than the direct radiative torque. Here, we consider the relatively simple case of a spheroidal grain. Given our best estimates for the photoelectric yield and other relevant grain physical properties, we find that the recoil torques contribute at the 10% level or less compared with the direct radiative torque. We recommend that the recoil torques not be included in models of radiation-driven grain alignment at this time. However, additional experimental characterization of the surface properties and photoelectric yield for sub-micron grains is needed to better quantify the magnitude of these torques.

  1. Design and testing of a non-intrusive torque measurement system

    E-Print Network [OSTI]

    Wilson, Edwin Ernest

    1998-01-01T23:59:59.000Z

    This thesis details the initial development of a non-intrusive torque measurement system to measure torque in a rotating driveshaft like those commonly found on internal combustion engine powered irrigation pumping plants. A typical driveshaft used...

  2. POPe689. (Submitted to Ap. J.) Radiative Torques on Interstellar Grains

    E-Print Network [OSTI]

    Draine, Bruce T.

    @phoenix.princeton.edu ABSTRACT Radiative torques on irregular dust grains, in addition to producing superthermal rotation, play

  3. Theory comparison and numerical benchmarking on neoclassical toroidal viscosity torque

    SciTech Connect (OSTI)

    Wang, Zhirui; Park, Jong-Kyu; Logan, Nikolas; Kim, Kimin; Menard, Jonathan E. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)] [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States); Liu, Yueqiang [Euratom/CCFE Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom)] [Euratom/CCFE Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom)

    2014-04-15T23:59:59.000Z

    Systematic comparison and numerical benchmarking have been successfully carried out among three different approaches of neoclassical toroidal viscosity (NTV) theory and the corresponding codes: IPEC-PENT is developed based on the combined NTV theory but without geometric simplifications [Park et al., Phys. Rev. Lett. 102, 065002 (2009)]; MARS-Q includes smoothly connected NTV formula [Shaing et al., Nucl. Fusion 50, 025022 (2010)] based on Shaing's analytic formulation in various collisionality regimes; MARS-K, originally computing the drift kinetic energy, is upgraded to compute the NTV torque based on the equivalence between drift kinetic energy and NTV torque [J.-K. Park, Phys. Plasma 18, 110702 (2011)]. The derivation and numerical results both indicate that the imaginary part of drift kinetic energy computed by MARS-K is equivalent to the NTV torque in IPEC-PENT. In the benchmark of precession resonance between MARS-Q and MARS-K/IPEC-PENT, the agreement and correlation between the connected NTV formula and the combined NTV theory in different collisionality regimes are shown for the first time. Additionally, both IPEC-PENT and MARS-K indicate the importance of the bounce harmonic resonance which can greatly enhance the NTV torque when EB drift frequency reaches the bounce resonance condition.

  4. A Sensorless Direct Torque Control Scheme Suitable for Electric Vehicles

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    A Sensorless Direct Torque Control Scheme Suitable for Electric Vehicles Farid Khoucha, Khoudir an Electric Vehicle (EV). The proposed scheme uses an adaptive flux and speed observer that is based on a full is a good candidate for EVs propulsion. Index Terms--Electric vehicle, Induction motor, sensorless drive

  5. Drive torque actuation in active surge control of centrifugal compressors

    E-Print Network [OSTI]

    Gravdahl, Jan Tommy

    Drive torque actuation in active surge control of centrifugal compressors Jan Tommy Gravdahl , Olav to active surge control is presented for a centrifugal compressor driven by an electrical motor. The main is considered to be the control input. The proposed method is simulated on a compressor model using

  6. Active surge control of centrifugal compressors using drive torque

    E-Print Network [OSTI]

    Gravdahl, Jan Tommy

    Active surge control of centrifugal compressors using drive torque Jan Tommy Gravdahl , Olav control is presented. A centrifugal compressor driven by an electrical motor is studied, and the drive of the drive as control ensures exponential convergence. The proposed method is simulated on a compressor model

  7. The Shaft Torque of a Tandem Axial-Piston Pump

    E-Print Network [OSTI]

    Manring, Noah D.

    The Shaft Torque of a Tandem Axial- Piston Pump Noah D. Manring Viral S. Mehta Mechanical of this study is to identify the best indexed position of two rotating groups within a tandem axial-piston pump characteristics of the pump, other vibration aspects of the machine are also expected to be reduced. In particular

  8. Damping Torque Estimation and Oscillatory Stability Margin Prediction

    E-Print Network [OSTI]

    Caizares, Claudio A.

    of linearized models of power systems is studied here as a possible on-line security index, based on system security monitoring of power systems. Index Terms-- Damping torque, system identification, oscilla- tory to investigate the accuracy of damping coefficient identified from on-line measurements using the ordinary least

  9. A comparison of statistical learning approaches for engine torque estimation

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    of the -insensitive norm in SVMs regularization weight factor engine speed (rotation/min) IC internal combustion: for example, automatically setting gears, optimizing engine perfor- mance, reducing emissions and designingA comparison of statistical learning approaches for engine torque estimation A. Rakotomamonjy1 , R

  10. Thermionic-photovoltaic energy converter

    SciTech Connect (OSTI)

    Chubb, D. L.

    1985-07-09T23:59:59.000Z

    A thermionic-photovoltaic energy conversion device comprises a thermionic diode mounted within a hollow tubular photovoltaic converter. The thermionic diode maintains a cesium discharge for producing excited atoms that emit line radiation in the wavelength region of 850 nm to 890 nm. The photovoltaic converter is a silicon or galium arsenide photovoltaic cell having bandgap energies in this same wavelength region for optimum cell efficiency.

  11. Friction Observer and Compensation for Control of Robots with Joint Torque Measurement

    E-Print Network [OSTI]

    De Luca, Alessandro

    Friction Observer and Compensation for Control of Robots with Joint Torque Measurement Luc Le Tien-- In this paper we introduce a friction observer for robots with joint torque sensing (in particular for the DLR. The observer output corresponds to the low-pass filtered friction torque. It is used for friction compensation

  12. An ultra-high precision, high bandwidth torque sensor for microrobotics applications

    E-Print Network [OSTI]

    Wood, Robert

    and testing of a custom single-axis torque sensor. The micorobots in question are too large for MEMS force of predicted torques is on the order of 1-10Nm. These values were obtained using a quasi-steady blade and manufacture of custom torque sensors for a variety This work was supported in part by the Army Research

  13. Development of a Whole-Sensitive Teleoperated Robot Arm using Torque Sensing Technique

    E-Print Network [OSTI]

    Tachi, Susumu

    Development of a Whole-Sensitive Teleoperated Robot Arm using Torque Sensing Technique Dzmitry-sensitive robot arm enabling torque measurement in each joint by means of developed optical torque sensors. When of corresponding robot arm joint. Thus, the whole structure of the manipulator can safely interact

  14. Closed-loop torque feedback for a universal field-oriented controller

    DOE Patents [OSTI]

    De Doncker, R.W.A.A.; King, R.D.; Sanza, P.C.; Haefner, K.B.

    1992-11-24T23:59:59.000Z

    A torque feedback system is employed in a universal field-oriented (UFO) controller to tune a torque-producing current command and a slip frequency command in order to achieve robust torque control of an induction machine even in the event of current regulator errors and during transitions between pulse width modulated (PWM) and square wave modes of operation. 1 figure.

  15. Pulsating Torque Reduction for Permanent Magnet Bojan Grcar, Peter Cafuta, Gorazd Stumberger

    E-Print Network [OSTI]

    Stankoviæ, Aleksandar

    vibration and acoustic noise which may be even amplified in variable speed drives when the torque frequencyPulsating Torque Reduction for Permanent Magnet AC Motors Bojan Grcar, Peter Cafuta, Gorazd motors are discussed in the paper. The pulsation torque is a consequence of the non-sinusoidal flux

  16. Fig. 1. Teleoperated slave robot. Optical Torque Sensors for Local Impedance Control

    E-Print Network [OSTI]

    Tachi, Susumu

    Fig. 1. Teleoperated slave robot. Optical Torque Sensors for Local Impedance Control Realization_teterukov@ipc.i.u-tokyo.ac.jp We recently developed an optical torque sensor to replace expensive strain-gauge-based sensor on the anthropomorphic robot arm and realize local impedance control in individual joints. Keywords: Optical torque

  17. Closed-loop torque feedback for a universal field-oriented controller

    DOE Patents [OSTI]

    De Doncker, Rik W. A. A. (Schenectady, NY); King, Robert D. (Schenectady, NY); Sanza, Peter C. (Clifton Park, NY); Haefner, Kenneth B. (Schenectady, NY)

    1992-01-01T23:59:59.000Z

    A torque feedback system is employed in a universal field-oriented (UFO) controller to tune a torque-producing current command and a slip frequency command in order to achieve robust torque control of an induction machine even in the event of current regulator errors and during transitions between pulse width modulated (PWM) and square wave modes of operation.

  18. Converting Biomass to High-Value Feedstocks

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Converting Biomass to High-Value Feedstocks Advanced feedstocks play an important role in economically and efficiently converting biomass into bioenergy products. Advanced...

  19. Sandia National Laboratories: wave energy converters

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    marine hydrokinetic (MHK) reference models (RMs) for wave energy converters and tidal, ocean, and river current energy converters. The RMP team includes a partnership between...

  20. Sandia National Laboratories: river current energy converters

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    marine hydrokinetic (MHK) reference models (RMs) for wave energy converters and tidal, ocean, and river current energy converters. The RMP team includes a partnership between...

  1. Sandia National Laboratories: tidal energy converters

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    marine hydrokinetic (MHK) reference models (RMs) for wave energy converters and tidal, ocean, and river current energy converters. The RMP team includes a partnership between...

  2. Speed And Power Control Of An Engine By Modulation Of The Load Torque

    DOE Patents [OSTI]

    Ziph, Benjamin (Ann Arbor, MI); Strodtman, Scott (Ypsilanti, MI); Rose, Thomas K (Chelsea, MI)

    1999-01-26T23:59:59.000Z

    A system and method of speed and power control for an engine in which speed and power of the engine is controlled by modulation of the load torque. The load torque is manipulated in order to cause engine speed, and hence power to be changed. To accomplish such control, the load torque undergoes a temporary excursion in the opposite direction of the desired speed and power change. The engine and the driven equipment will accelerate or decelerate accordingly as the load torque is decreased or increased, relative to the essentially fixed or constant engine torque. As the engine accelerates or decelerates, its power increases or decreases in proportion.

  3. Avoidance of Tearing Mode Locking and Disruption with Electro-Magnetic Torque Introduced by Feedback-based Mode Rotation Control in DIII-D and RFX-mod

    SciTech Connect (OSTI)

    Okabayashi, M. [PPPL; Zanca, P. [Euratom-ENEA; Strait, E. J. [General Atomics

    2014-09-01T23:59:59.000Z

    Disruptions caused by tearing modes (TMs) are considered to be one of the most critical roadblocks to achieving reliable, steady-state operation of tokamak fusion reactors. Here we have demonstrated a very promising scheme to avoid such disruptions by utilizing the electro-magnetic (EM) torque produced with 3D coils that are available in many tokamaks. In this scheme, the EM torque to the modes is created by a toroidal phase shift between the externally-applied field and the excited TM fields, compensating for the mode momentum loss due to the interaction with the resistive wall and uncorrected error fields. Fine control of torque balance is provided by a feedback scheme. We have explored this approach in two vastly different devices and plasma conditions: DIII-D and RFX-mod operated in tokamak mode. In DIII-D, the plasma target was high ?N plasmas in a non-circular divertor tokamak. In RFX-mod, the plasma was ohmically-heated plasma with ultralow safety factor in a circular limiter discharge of active feedback coils outside the thick resistive shell. The DIII-D and RFX-mod experiments showed remarkable consistency with theoretical predictions of torque balance. The application to ignition-oriented devices such as International Thermonuclear Experimental Reactor (ITER) would expand the horizon of its operational regime. The internal 3D coil set currently under consideration for edge localized mode suppression in ITER would be well suited to this purpose.

  4. A thermionic converter success story

    SciTech Connect (OSTI)

    Donovan, B.D.; Lamp, T.R. (Aerospace Power Division, Wright Laboratory Wright-Patterson AFB, OH 45433-6563 (United States)); Ramaligam, M.L. (UES, Inc. 4401 Dayton-Xenia Road, Dayton, OH 45432-1894 (United States))

    1993-01-20T23:59:59.000Z

    This paper summarizes the advanced out-of-core thermionic technology program being managed at Wright Laboratory: The Thermionic Critical Technology (TCT) Investigation. This program has been supported primarily by the United State Air Force for design and fabrication, and supported by Strategic Defense Initiative Organization (SDIO) for performance and life testing efforts. Converter design parameters, specifications, and performance testing data is summarized. Converters fabricated by Loral Electro Optical Systems (Loral EOS) under this program have exceeding performance requirements, and have demonstrated efficiencies as high as 14%.

  5. Power converters for parabolic dishes

    SciTech Connect (OSTI)

    Truscello, V.C.; Williams, A.N.

    1981-01-01T23:59:59.000Z

    The development status of receivers and power conversion units to be used with parabolic dish concentrators is presented. Applications are identified, and the key role played by the power converter element of the collector module is emphasized. The electrical output of the 11-meter-diameter dish modules which are being developed varies up to a maximum of about 25 kilowatts, depending on the thermodynamic cycle of the power converter. Three power conversion units are being developed: an organic Rankine, an air Brayton, and a Stirling. The development program for the receivers and the power conversion units is described in detail.

  6. Angular momentum and torque described with the complex octonion

    SciTech Connect (OSTI)

    Weng, Zi-Hua, E-mail: xmuwzh@xmu.edu.cn [School of Physics and Mechanical and Electrical Engineering, Xiamen University, Xiamen 361005 (China)

    2014-08-15T23:59:59.000Z

    The paper aims to adopt the complex octonion to formulate the angular momentum, torque, and force etc in the electromagnetic and gravitational fields. Applying the octonionic representation enables one single definition of angular momentum (or torque, force) to combine some physics contents, which were considered to be independent of each other in the past. J. C. Maxwell used simultaneously two methods, the vector terminology and quaternion analysis, to depict the electromagnetic theory. It motivates the paper to introduce the quaternion space into the field theory, describing the physical feature of electromagnetic and gravitational fields. The spaces of electromagnetic field and of gravitational field can be chosen as the quaternion spaces, while the coordinate component of quaternion space is able to be the complex number. The quaternion space of electromagnetic field is independent of that of gravitational field. These two quaternion spaces may compose one octonion space. Contrarily, one octonion space can be separated into two subspaces, the quaternion space and S-quaternion space. In the quaternion space, it is able to infer the field potential, field strength, field source, angular momentum, torque, and force etc in the gravitational field. In the S-quaternion space, it is capable of deducing the field potential, field strength, field source, current continuity equation, and electric (or magnetic) dipolar moment etc in the electromagnetic field. The results reveal that the quaternion space is appropriate to describe the gravitational features, including the torque, force, and mass continuity equation etc. The S-quaternion space is proper to depict the electromagnetic features, including the dipolar moment and current continuity equation etc. In case the field strength is weak enough, the force and the continuity equation etc can be respectively reduced to that in the classical field theory.

  7. Angular momentum and torque described with the complex octonion

    E-Print Network [OSTI]

    Zi-Hua Weng

    2014-08-19T23:59:59.000Z

    The paper aims to adopt the complex octonion to formulate the angular momentum, torque, and force etc in the electromagnetic and gravitational fields. Applying the octonionic representation enables one single definition of angular momentum (or torque, force) to combine some physics contents, which were considered to be independent of each other in the past. J. C. Maxwell used simultaneously two methods, the vector terminology and quaternion analysis, to depict the electromagnetic theory. It motivates the paper to introduce the quaternion space into the field theory, describing the physical feature of electromagnetic and gravitational fields. The spaces of two fields can be chosen as the quaternion spaces, while the coordinate component of quaternion space is able to be the complex number. The quaternion space of electromagnetic field is independent of that of gravitational field. These two quaternion spaces may compose one octonion space. Contrarily, one octonion space can be separated into two subspaces, the quaternion space and S-quaternion space. In the quaternion space, it is able to infer the field potential, field strength, field source, angular momentum, torque, and force etc in the gravitational field. In the S-quaternion space, it is capable of deducing the field potential, field strength, field source, current continuity equation, and electric (or magnetic) dipolar moment etc in the electromagnetic field. The results reveal that the quaternion space is appropriate to describe the gravitational features, including the torque, force, and mass continuity equation etc. The S-quaternion space is proper to depict the electromagnetic features, including the dipolar moment and current continuity equation etc. In case the field strength is weak enough, the force and the continuity equation etc can be respectively reduced to that in the classical field theory.

  8. Property Loss / Damage Report Damage Loss Details

    E-Print Network [OSTI]

    Ponce, V. Miguel

    Property Loss / Damage Report Damage Loss Details Date & Time of Damage / Loss: Type of damage / loss: Location - specific address / room: Project / Grant associated with damage / loss - grant Police: When was damage / loss first discovered - BY WHOM: Pictures available or attached? Was personal

  9. Torque on an exoplanet from an anisotropic evaporative wind

    E-Print Network [OSTI]

    Teyssandier, Jean; Adams, Fred C; Quillen, Alice C

    2015-01-01T23:59:59.000Z

    Winds from short-period Earth and Neptune mass exoplanets, driven by high energy radiation from a young star, may evaporate a significant fraction of a planet's mass. If the momentum flux from the evaporative wind is not aligned with the planet/star axis, then it can exert a torque on the planet's orbit. Using steady-state one-dimensional evaporative wind models we estimate this torque using a lag angle that depends on the product of the speed of the planet's upper atmosphere and a flow timescale for the wind to reach its sonic radius. We also estimate the momentum flux from time-dependent one-dimensional hydrodynamical simulations. We find that only in a very narrow regime in planet radius, mass and stellar radiation flux is a wind capable of exerting a significant torque on the planet's orbit. Similar to the Yarkovsky effect, the wind causes the planet to drift outward if atmospheric circulation is prograde (super-rotating) and in the opposite direction if the circulation is retrograde. A close-in super Ear...

  10. Magnetic Torque of Microfabricated Elements and Magnetotactic Bacteria

    E-Print Network [OSTI]

    Lars Zondervan; zlem Sardan Sukas; Islam S. M. Khalil; Marc P. Pichel; Sarthak Misra; Leon Abelmann

    2014-08-07T23:59:59.000Z

    We present a thorough theoretical analysis of the magnetic torque on microfabricated elements with dimensions in the range of 100 to 500 {\\mu}m and magneto-somes of magnetotactic bacteria of a few {\\mu}m length. We derive simple equations for field dependent torque and magnetic shape anisotropy that can be readily used to replace the crude approximations commonly used. We illustrate and verify the theory on microfabricated elements and magnetotactic bacteria, by field depedent torque magnetometry and by observing their rotation in water under application of a rotating magnetic field. The maximum rotation frequency of the largest microfabricated elements agrees within error boundaries with theory. For smaller, and especially thinner, elements the measured frequencies are a factor of three to four too low. We suspect this is caused by incomplete saturation of the magnetisation in the elements, which is not incorporated in our model. The maximum rotation frequency of magnetotactic bacteria agrees with our model within error margins, which are however quite big due to the large spread in bacteria morphology. The model presented provides a solid basis for the analysis of experiments with magnetic objects in liquid, which is for instance the case in the field of medical microrobotics.

  11. Charge-pump voltage converter

    DOE Patents [OSTI]

    Brainard, John P. (Albuquerque, NM); Christenson, Todd R. (Albuquerque, NM)

    2009-11-03T23:59:59.000Z

    A charge-pump voltage converter for converting a low voltage provided by a low-voltage source to a higher voltage. Charge is inductively generated on a transfer rotor electrode during its transit past an inductor stator electrode and subsequently transferred by the rotating rotor to a collector stator electrode for storage or use. Repetition of the charge transfer process leads to a build-up of voltage on a charge-receiving device. Connection of multiple charge-pump voltage converters in series can generate higher voltages, and connection of multiple charge-pump voltage converters in parallel can generate higher currents. Microelectromechanical (MEMS) embodiments of this invention provide a small and compact high-voltage (several hundred V) voltage source starting with a few-V initial voltage source. The microscale size of many embodiments of this invention make it ideally suited for MEMS- and other micro-applications where integration of the voltage or charge source in a small package is highly desirable.

  12. Phase-Shifted Full Bridge DC-DC Converter with Energy Recovery Clamp and Reduced Circulating Current

    E-Print Network [OSTI]

    of the switch conduction and turn-off losses achieved by an energy recovery secondary clamp circuit an improved PSFB DC-DC converter using only a modified energy recovery clamp circuit attached at the secondaryPhase-Shifted Full Bridge DC-DC Converter with Energy Recovery Clamp and Reduced Circulating

  13. Portable convertible blast effects shield

    DOE Patents [OSTI]

    Pastrnak, John W. (Livermore, CA); Hollaway, Rocky (Modesto, CA); Henning, Carl D. (Livermore, CA); Deteresa, Steve (Livermore, CA); Grundler, Walter (Hayward, CA); Hagler, Lisle B. (Berkeley, CA); Kokko, Edwin (Dublin, CA); Switzer, Vernon A. (Livermore, CA)

    2011-03-15T23:59:59.000Z

    A rapidly deployable portable convertible blast effects shield/ballistic shield includes a set two or more frusto-conically-tapered telescoping rings operably connected to each other to convert between a telescopically-collapsed configuration for storage and transport, and a telescopically-extended upright configuration forming an expanded inner volume. In a first embodiment, the upright configuration provides blast effects shielding, such as against blast pressures, shrapnel, and/or fire balls. And in a second embodiment, the upright configuration provides ballistic shielding, such as against incoming weapons fire, shrapnel, etc. Each ring has a high-strength material construction, such as a composite fiber and matrix material, capable of substantially inhibiting blast effects and impinging projectiles from passing through the shield. And the set of rings are releasably securable to each other in the telescopically-extended upright configuration by the friction fit of adjacent pairs of frusto-conically-tapered rings to each other.

  14. Portable convertible blast effects shield

    DOE Patents [OSTI]

    Pastrnak, John W. (Livermore, CA); Hollaway, Rocky (Modesto, CA); Henning, Carl D. (Livermore, CA); Deteresa, Steve (Livermore, CA); Grundler, Walter (Hayward, CA); Hagler, Lisle B. (Berkeley, CA); Kokko, Edwin (Dublin, CA); Switzer, Vernon A (Livermore, CA)

    2007-05-22T23:59:59.000Z

    A rapidly deployable portable convertible blast effects shield/ballistic shield includes a set two or more telescoping cylindrical rings operably connected to each other to convert between a telescopically-collapsed configuration for storage and transport, and a telescopically-extended upright configuration forming an expanded inner volume. In a first embodiment, the upright configuration provides blast effects shielding, such as against blast pressures, shrapnel, and/or fire balls. And in a second embodiment, the upright configuration provides ballistic shielding, such as against incoming weapons fire, shrapnel, etc. Each ring has a high-strength material construction, such as a composite fiber and matrix material, capable of substantially inhibiting blast effects and impinging projectiles from passing through the shield. And the set of rings are releasably securable to each other in the telescopically-extended upright configuration, such as by click locks.

  15. Portable convertible blast effects shield

    DOE Patents [OSTI]

    Pastrnak, John W. (Livermore, CA); Hollaway, Rocky (Modesto, CA); Henning, Carl D. (Livermore, CA); Deteresa, Steve (Livermore, CA); Grundler, Walter (Hayward, CA); Hagler,; Lisle B. (Berkeley, CA); Kokko, Edwin (Dublin, CA); Switzer, Vernon A (Livermore, CA)

    2010-10-26T23:59:59.000Z

    A rapidly deployable portable convertible blast effects shield/ballistic shield includes a set two or more telescoping cylindrical rings operably connected to each other to convert between a telescopically-collapsed configuration for storage and transport, and a telescopically-extended upright configuration forming an expanded inner volume. In a first embodiment, the upright configuration provides blast effects shielding, such as against blast pressures, shrapnel, and/or fire balls. And in a second embodiment, the upright configuration provides ballistic shielding, such as against incoming weapons fire, shrapnel, etc. Each ring has a high-strength material construction, such as a composite fiber and matrix material, capable of substantially inhibiting blast effects and impinging projectiles from passing through the shield. And the set of rings are releasably securable to each other in the telescopically-extended upright configuration, such as by click locks.

  16. Collector for thermionic energy converter

    SciTech Connect (OSTI)

    Bell, R.L.

    1981-07-21T23:59:59.000Z

    An improved collector is provided for a thermionic energy converter. The collector comprises a p-type layer of a semiconductor material formed on an n-type layer of a semiconductor material. The p-n junction is maintained in a forward biased condition. The electron affinity of the exposed surface of the p-type layer is effectively lowered to a low level near zero by the presence of a work function lowering activator. The dissipation of energy during collection is reduced by the passage of electrons through the p-type layer in the metastable conduction band state. A significant portion of the electron current remains at the potential of the fermi level of the n-type layer rather than dropping to the fermi level of the p-type layer. Less energy is therefore dissipated as heat and a higher net power output is delivered from a thermionic energy converter incorporating the collector.

  17. Torque for electron spin induced by electron permanent electric dipole moment

    SciTech Connect (OSTI)

    Senami, Masato, E-mail: senami@me.kyoto-u.ac.jp, E-mail: akitomo@scl.kyoto-u.ac.jp; Fukuda, Masahiro, E-mail: senami@me.kyoto-u.ac.jp, E-mail: akitomo@scl.kyoto-u.ac.jp; Ogiso, Yoji, E-mail: senami@me.kyoto-u.ac.jp, E-mail: akitomo@scl.kyoto-u.ac.jp; Tachibana, Akitomo, E-mail: senami@me.kyoto-u.ac.jp, E-mail: akitomo@scl.kyoto-u.ac.jp [Department of Micro Engineering, Kyoto University, Kyoto 615-8540 (Japan)

    2014-10-06T23:59:59.000Z

    The spin torque of the electron is studied in relation to the electric dipole moment (EDM) of the electron. The spin dynamics is known to be given by the spin torque and the zeta force in quantum field theory. The effect of the EDM on the torque of the spin brings a new term in the equation of motion of the spin. We study this effect for a solution of the Dirac equation with electromagnetic field.

  18. Universal adaptive torque control for PM motors for field-weakening region operation

    DOE Patents [OSTI]

    Royak, Semyon (Beachwood, OH); Harbaugh, Mark M. (Richfield, OH); Breitzmann, Robert J. (South Russel, OH); Nondahl, Thomas A. (Wauwatosa, WI); Schmidt, Peter B. (Franklin, WI); Liu, Jingbo (Milwaukee, WI)

    2011-03-29T23:59:59.000Z

    The invention includes a motor controller and method for controlling a permanent magnet motor. In accordance with one aspect of the present technique, a permanent magnet motor is controlled by, among other things, receiving a torque command, determining a normalized torque command by normalizing the torque command to a characteristic current of the motor, determining a normalized maximum available voltage, determining an inductance ratio of the motor, and determining a direct-axis current based upon the normalized torque command, the normalized maximum available voltage, and the inductance ratio of the motor.

  19. SPIN-TORQUE IN SYSTEMS WITH INHOMOGENEOUS MAGETIZATION

    SciTech Connect (OSTI)

    Zangwill, Andrew [Georgia Institute of Technology

    2013-04-23T23:59:59.000Z

    The work performed during the grant period focused on the phenomenon of spin-transfer torque. This is a quantum mechanical effect whereby the angular momentum of conduction electrons is transferred to the magnetization of ferromagnetic structures. Our work on this subject began with phenomenological drift-diffusion and Landau-Lifshitz-Gilbert equations to demonstrate unambiguously that unpolarized current flow from a nonmagnet into a ferromagnet can produce a precession-type instability of the magnetization. We then used Boltzmann calculations appropriate to spin-valve type magnetic heterostructures composed of a non-magnetic thin film sandwiched between two thin film layers with uniform magnetization. Perhaps our most important paper dealt with quantum and semi-classical calculations of spin-transfer torque in systems with domain walls and other inhomogeneous distributions of magnetization. The latter work caused us to suggest that the Landau-Lifshitz approach to magnetic damping provided a clearer picture of the physics than the more popular (but formally equivalent) Gilbert approach to damping. Finally, we returned to our Boltzmann calculations and made a serious effort to analyze experimental data on current-induced magnetization in switching in magnetic spin-valve structures. Our work was part of a world-wide effort to study and harness the transport of the electron's spin and was one of the first sustained theoretical efforts in this direction in the United States. The payoff is just now being seen. In November of 2012, the Everspin Corporation announced the release of the first commercial spin-torque magnetoresistive random access memory.

  20. COMMUNITY ALERT INCIDENT: Catalytic Converter Thefts

    E-Print Network [OSTI]

    Rose, Michael R.

    converter is a part used to reduce the toxicity of emissions from an internal combustion engine. What can

  1. CONVERTIBLE BONDS IN A DEFAULTABLE DIFFUSION MODEL

    E-Print Network [OSTI]

    Jeanblanc, Monique

    CONVERTIBLE BONDS IN A DEFAULTABLE DIFFUSION MODEL Tomasz R. Bielecki Department of Applied Research Grant PS12918. #12;2 Convertible Bonds in a Defaultable Diffusion Model 1 Introduction In [4), such as Convertible Bonds (CB), and we provided a rigorous decomposition of a CB into a bond component and a (game

  2. Auxiliary resonant DC tank converter

    DOE Patents [OSTI]

    Peng, Fang Z. (Knoxville, TN)

    2000-01-01T23:59:59.000Z

    An auxiliary resonant dc tank (ARDCT) converter is provided for achieving soft-switching in a power converter. An ARDCT circuit is coupled directly across a dc bus to the inverter to generate a resonant dc bus voltage, including upper and lower resonant capacitors connected in series as a resonant leg, first and second dc tank capacitors connected in series as a tank leg, and an auxiliary resonant circuit comprising a series combination of a resonant inductor and a pair of auxiliary switching devices. The ARDCT circuit further includes first clamping means for holding the resonant dc bus voltage to the dc tank voltage of the tank leg, and second clamping means for clamping the resonant dc bus voltage to zero during a resonant period. The ARDCT circuit resonantly brings the dc bus voltage to zero in order to provide a zero-voltage switching opportunity for the inverter, then quickly rebounds the dc bus voltage back to the dc tank voltage after the inverter changes state. The auxiliary switching devices are turned on and off under zero-current conditions. The ARDCT circuit only absorbs ripples of the inverter dc bus current, thus having less current stress. In addition, since the ARDCT circuit is coupled in parallel with the dc power supply and the inverter for merely assisting soft-switching of the inverter without participating in real dc power transmission and power conversion, malfunction and failure of the tank circuit will not affect the functional operation of the inverter; thus a highly reliable converter system is expected.

  3. Digital control of HVDC converters

    SciTech Connect (OSTI)

    Pilotto, L.A.S.; Roitman, M.; Alves, J.E.R.

    1989-05-01T23:59:59.000Z

    This paper presents the project of a completely digital HVDC converter controller based on a 16-bit microcomputer. It was decided to achieve as much as possible by software in order to minimize functions performed by external hardware. The presented design comprises software programmed functions such as a PID current control amplifier, voltage dependent current order limiters and an alpha-minimum symmetrization unit, among others. HVDC control principles are briefly reviewed and a detailed description of both the hardware and software structure of the controller is presented. The digital controller was implemented in an HVDC simulator and several dynamic performance tests demonstrated the efficiency of the proposed methodology.

  4. Converting Energy to Medical Progress

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOnItem NotEnergy, science, and technology-- Energy, science, and technologyConverting to

  5. Resistive wall tearing mode generated finite net electromagnetic torque in a static plasma

    SciTech Connect (OSTI)

    Hao, G. Z., E-mail: haogz@swip.ac.cn; Wang, A. K.; Xu, M.; Qu, H. P.; Peng, X. D.; Wang, Z. H.; Xu, J. Q.; Qiu, X. M. [Southwestern Institute of Physics, Post Office Box 432, Chengdu 610041 (China)] [Southwestern Institute of Physics, Post Office Box 432, Chengdu 610041 (China); Liu, Y. Q. [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom)] [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom)

    2014-01-15T23:59:59.000Z

    The MARS-F code [Y. Q. Liu et al., Phys. Plasmas 7, 3681 (2000)] is applied to numerically investigate the effect of the plasma pressure on the tearing mode stability as well as the tearing mode-induced electromagnetic torque, in the presence of a resistive wall. The tearing mode with a complex eigenvalue, resulted from the favorable averaged curvature effect [A. H. Glasser et al., Phys. Fluids 18, 875 (1975)], leads to a re-distribution of the electromagnetic torque with multiple peaking in the immediate vicinity of the resistive layer. The multiple peaking is often caused by the sound wave resonances. In the presence of a resistive wall surrounding the plasma, a rotating tearing mode can generate a finite net electromagnetic torque acting on the static plasma column. Meanwhile, an equal but opposite torque is generated in the resistive wall, thus conserving the total momentum of the whole plasma-wall system. The direction of the net torque on the plasma is always opposite to the real frequency of the mode, agreeing with the analytic result by Pustovitov [Nucl. Fusion 47, 1583 (2007)]. When the wall time is close to the oscillating time of the tearing mode, the finite net torque reaches its maximum. Without wall or with an ideal wall, no net torque on the static plasma is generated by the tearing mode. However, re-distribution of the torque density in the resistive layer still occurs.

  6. Fig. 1 Teleoperated slave robot Development of Distributed Optical Torque Sensors for Realization of Local Impedance

    E-Print Network [OSTI]

    Tachi, Susumu

    Fig. 1 Teleoperated slave robot Development of Distributed Optical Torque Sensors for Realization the recent development of optical torque sensor in order to replace expensive strain gauge sensor attached shapes of mechanical structure of sensor as well as optical measurement approaches are given. The results

  7. How Fo-ATPase generates rotary torque George Oster, Hongyun Wang and Michael Grabe

    E-Print Network [OSTI]

    Oster, George

    of California, Berkeley, CA 94720-3112, USA The F-ATPases synthesize ATP using a transmembrane ionmotive force to a rotary torque in the transmem- brane Fo portion. This torque is communicated from Fo to the F1 portion to Boyer's binding change mechanism. Here we explain the principle by which an IMF generates this rotary

  8. Direct torque control of permanent magnet synchronous motors with non-sinusoidal back-EMF

    E-Print Network [OSTI]

    Ozturk, Salih Baris

    2009-05-15T23:59:59.000Z

    torque control of permanent magnet synchronous motor (PMSM) with sinusoidal back-EMF is discussed in detail. Secondly, the proposed two-phase conduction mode for DTC of BLDC motors is introduced in the constant torque region. In this control scheme, only...

  9. GAISUS-1 thermionic converter for the integrated solar upper stage

    SciTech Connect (OSTI)

    Begg, L.L.; Heffernan, T.F.; Horner, M.H. [General Atomics, San Diego, CA (United States)

    1997-12-31T23:59:59.000Z

    The Integrated Solar Upper Stage (ISUS) system is a compact orbital transfer vehicle which generates thrust to boost payloads from LEO to higher orbits. It does this by collecting and concentrating solar flux into a sensible thermal storage, graphite receiver which is used to heat hydrogen propellant to temperatures of up to 2500 K. The ISUS receiver also radiates heat into an array of thermionic converters which produce electrical power. The GAISUS-1 thermionic converter is a first generation planar converter designed to produce electrical power when coupled with the ISUS receiver. GAISUS-1 will deliver over 31 W{sub e} at 1900 K. A wrought Re hotshoe accepts radiant heat from the receiver. The back side of the hotshoe forms the emitting surface of the converter. Special attention was paid to optimize the electrical and thermal losses experienced through the sleeve. Triple and single sleeve geometries were thermally modeled and evaluated, resulting in the selection of a single sleeve design. A high temperature metal/ceramic seal isolates the emitter sleeve from the collector. A Nb collector is used and is an integral part of a Nb/Na heat pipe. The heat pipe transports reject heat from the collector surface to a thermal radiator (condenser) portion of the heat pipe. The converter utilizes an integral graphite Cs reservoir. This type of reservoir automatically produces a rise in Cs pressure in response to a rise in emitter/collector temperatures. This Cs pressure feedback mechanism insures adequate Cs coverage of the emitter over a broad range of operating conditions (temperatures).

  10. DA/MA: Multi-objective optimization of LCC resonant converter applied in high-voltage generator

    E-Print Network [OSTI]

    Paderborn, Universitt

    , transformer, and a cascaded rectifier, is shown below. Particular task of this project is to reduce power losses, volume, and stress of the components with the designated input and output specifications and the analytical converter large-signal model. Expected study and research work includes: Extend the power loss

  11. Thermionic converter emitter support arrangement

    SciTech Connect (OSTI)

    Allen, Daniel T. (La Jolla, CA)

    1990-01-01T23:59:59.000Z

    A support is provided for use in a therminonic converter to support an end of an emitter to keep it out of contact with a surrounding collector while allowing the emitter end to move axially as its temperature changes. The emitter end (34) is supported by a spring structure (44) that includes a pair of Belleville springs, and the spring structure is supported by a support structure (42) fixed to the housing that includes the collector. The support structure is in the form of a sandwich with a small metal spring-engaging element (74) at the front end, a larger metal main support (76) at the rear end that is attached to the housing, and with a ceramic layer (80) between them that is bonded by hot isostatic pressing to the metal element and metal main support. The spring structure can include a loose wafer (120) captured between the Belleville springs.

  12. Thermionic converter emitter support arrangement

    SciTech Connect (OSTI)

    Allen, D.T.

    1990-10-16T23:59:59.000Z

    A support is presented for use in a thermionic converted to support an end of an emitter to keep it out of contact with a surrounding collector while allowing the emitter end to move axially at its temperatures changes. The emitter end is supported by a spring structure that includes a pair of Belleville springs, and the spring structure is supported by a support structure fixed to the housing that includes the collector. The support structure is in the form of a sandwich with a small metal spring-engaging element at the front end, a large metal main support at the rear end that is attached to the housing, and metal main support. The spring structure can include a loose wafer captured between the Belleville springs.

  13. Thermionic converter emitter support arrangement

    SciTech Connect (OSTI)

    Allen, Daniel T. (La Jolla, CA)

    1990-01-01T23:59:59.000Z

    A support is provided for use in a thermionic converter to support an end an emitter to keep it out of contact with a surrounding collector while allowing the emitter end to move axially at its temperatures changes. The emitter end (34) is supported by a spring structure (44) that includes a pair of Belleville springs, and the spring structure is supported by a support structure (42) fixed to the housing that includes the collector. The support structure is in the form of a sandwich with a small metal spring-engaging element (74) at the front end, a larger metal main support (76) at the rear end that is attached to the housng, and with a ceramic layer (80) between them that is bonded by hot isostatic pressing to the metal element and metal main support. The spring structure can include a loose wafer (120) captured between the Belleville springs.

  14. Thermionic converter emitter support arrangement

    SciTech Connect (OSTI)

    Allen, D.T.

    1989-07-06T23:59:59.000Z

    This document discusses a support provided for use in a thermionic converter to support an end of an emitter to keep it out of contact with a surrounding collector while allowing the emitter end to move axially as its temperature changes. The emitter end is supported by a spring structure that includes a pair of Belleville springs, and the spring structure is supported by a support structure fixed to the housing that includes the collector. The support structure is in the form of a sandwich with a small metal spring-engaging element at the front end, a larger metal main support at the rear end that is attached to the housing, and with a ceramic layer between them that is bonded by hot isostatic pressing to the metal element and metal main support. The spring structure can include a loose wafer captured between the Belleville springs. 7 figs.

  15. Thermionic converter emitter support arrangement

    SciTech Connect (OSTI)

    Allen, D.T.

    1990-05-22T23:59:59.000Z

    This patent describes a support provided for use in a therminonic converter to support an end of an emitter to keep it out of contact with a surrounding collector while allowing the emitter end to move axially as its temperature changes. The emitter end is supported by a spring structure that includes a pair of Belleville springs, and the spring structure is supported by a support structure fixed to the housing that includes the collector. The support structure is in the form of a sandwich with a small metal spring-engaging element at the front end, a larger metal main support at the rear end that is attached to the housing, and with a ceramic layer between them that is bonded by hot isostatic pressing to the metal element and metal main support. The spring structure can include a loose wafer captured between the Belleville springs.

  16. Magnetization reversal driven by a spin torque oscillator

    SciTech Connect (OSTI)

    Sbiaa, R., E-mail: rachid@squ.edu.om [Department of Physics, Sultan Qaboos University, P.O. Box 36, PC 123 Muscat (Oman)

    2014-09-01T23:59:59.000Z

    Magnetization reversal of a magnetic free layer under spin transfer torque (STT) effect from a magnetic hard layer with a fixed magnetization direction and an oscillating layer is investigated. By including STT from the oscillating layer with in-plane anisotropy and orthogonal polarizer, magnetization-time dependence of free layer is determined. The results show that the frequency and amplitude of oscillations can be varied by adjusting the current density and magnetic properties. For an optimal oscillation frequency (f{sub opt}), a reduction of the switching time (t{sub 0}) of the free layer is observed. Both f{sub opt} and t{sub 0} increase with the anisotropy field of the free layer.

  17. Sandia National Laboratories: wave energy converter

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    release. This model has ... Sandia Funded to Model Power Pods for Utility-Scale Wave-Energy Converter On September 16, 2014, in Computational Modeling & Simulation, Energy,...

  18. New Catalyst Converts CO2 to Fuel

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    a catalyst that improves their system for converting waste carbon dioxide (CO) into syngas, a precursor of gasoline and other energy-rich products, bringing the process closer...

  19. Bi-directional dc-dc Converter

    Broader source: Energy.gov (indexed) [DOE]

    Purpose of Work for FY08 1. Vehicle modeling, simulation, and operation voltages optimization. 2. DC-DC Power converter and control modeling. 3. Silicon Carbide device...

  20. Sandia National Laboratories: current energy converter array...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    array optimization framework Current Energy Converter Array Optimization Framework On March 13, 2014, in Computational Modeling & Simulation, Energy, News, News & Events,...

  1. Sandia National Laboratories: ocean energy converters

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    ocean energy converters DOE-Sponsored Reference Model Project Results Released On January 28, 2014, in Computational Modeling & Simulation, Energy, News, News & Events,...

  2. DC-DC converter current source fed naturally commutated brushless DC motor drive

    E-Print Network [OSTI]

    Khopkar, Rahul Vijaykumar

    2004-11-15T23:59:59.000Z

    inductor and the huge number of turns needed to achieve these values of the inductances lead to huge resistive losses. Therefore, it is shown that it is possible to replace the controlled rectifier and the large inductor with a suitable dc-dc converter...

  3. A chiral route to pulling optical forces and left-handed optical torques

    E-Print Network [OSTI]

    Canaguier-Durand, Antoine

    2015-01-01T23:59:59.000Z

    We analyze how chirality can generate pulling optical forces and left-handed torques by cross-coupling linear-to-angular momenta between the light field and the chiral object. In the dipolar regime, we reveal that such effects can emerge from a competition between non-chiral and chiral contributions to dissipative optical forces and torques, a competition balanced by the strength of chirality of the object. We extend the analysis to large chiral spheres where the interplay between chirality and multipolar resonances can give rise to a break of symmetry that flips the signs of both optical forces and torques.

  4. A study of the relationship between applied and effective torque on screw fastenings

    E-Print Network [OSTI]

    Lewis, Robert Miller

    1959-01-01T23:59:59.000Z

    from a nutrunner oould be very small and still result in a muoh larger variation of effeotive torque due to the other factors. This is ths problem which manufacturers of these types of air tools face and this research is devoted toward developing... the effeotive torque, Kany applied torque measuring instruments are some form of a transmission dynamometer (5) (6) (7) (8). This type of measuring devioe "may be desoribed as an instrument which is interposed between a prime mover and the apparatus which...

  5. Analysis of emitter material transport in thermionic converter

    SciTech Connect (OSTI)

    Paramonov, D.V.; El-Genk, M.S. [Institute for Space and Nuclear Power Studies, Chemical and Nuclear Engineering Department, University of New Mexico, Albuquerque, New Mexico 87131 (United States)

    1996-03-01T23:59:59.000Z

    Output power and efficiency of a thermionic converter depend on temperatures, cesiated work functions, and emissivities of electrodes as well as the interelectrode gap size. Operation lifetime of a thermionic converter is directly related to the values as well as the stability of these parameters, which can be seriously altered by the transport of emitter material to the collector during operation. Loss rate of tungsten, a preferred emitter material, by sublimation at typical operating temperatures is small (about 3{times}10{sup 7} atom/cm{sup 2}sec at 2000 K). The loss rate, however, can be several orders of magnitude higher in the presence of gaseous contaminants. Accelerated transport of emitter material to collector surface changes the effective emissivity and work functions of the electrodes, resulting in performance degradation. A phenomenological model was developed to simulate emitter material transport to the collector in the presence of oxygen, water vapor, and carbon oxide contaminants. The model accounts for interaction of these contaminants with both emitter and collector. Model results were in agreement with experimental data and theoretical results of other investigators. An analysis was performed to determine steady-state chemical composition of deposited material onto the collector surface in the presence of H{sub 2}O, O{sub 2}, and H{sub 2} gaseous contaminants. {copyright} {ital 1996 American Institute of Physics.}

  6. Vacuum-insulated catalytic converter

    DOE Patents [OSTI]

    Benson, David K. (Golden, CO)

    2001-01-01T23:59:59.000Z

    A catalytic converter has an inner canister that contains catalyst-coated substrates and an outer canister that encloses an annular, variable vacuum insulation chamber surrounding the inner canister. An annular tank containing phase-change material for heat storage and release is positioned in the variable vacuum insulation chamber a distance spaced part from the inner canister. A reversible hydrogen getter in the variable vacuum insulation chamber, preferably on a surface of the heat storage tank, releases hydrogen into the variable vacuum insulation chamber to conduct heat when the phase-change material is hot and absorbs the hydrogen to limit heat transfer to radiation when the phase-change material is cool. A porous zeolite trap in the inner canister absorbs and retains hydrocarbons from the exhaust gases when the catalyst-coated substrates and zeolite trap are cold and releases the hydrocarbons for reaction on the catalyst-coated substrate when the zeolite trap and catalyst-coated substrate get hot.

  7. High performance, close-spaced thermionic converters

    SciTech Connect (OSTI)

    Dick, R.S.; Britt, E.J.; Fitzpatrick, G.O.; McVey, J.B.

    1983-08-01T23:59:59.000Z

    Near ideal performance in a Thermionic Energy Converter (TEC) can be obtained using extremely small (< 10 microns) interelectrode spacings. Previous efforts to build such converters have encountered engineering problems. A new type of converter, called SAVTEC (for Self-Adjusting, Versatile Thermionic Energy Converter) has been developed at Rasor Associates, Inc., as a practical way to achieve small spacings. It has been demonstrated to deliver improved performance over conventional, ignited-mode converters. A series of individual SAVTEC's have been built and tested. Two general configurations were built: in the first a single emitter support lead (0.25 mm wire) passes through a hole in the center of the collector, with the emitter being welded to it. In the second three smaller wires replace the center wire and are welded to the emitter perimeter. These converters have shown reliable, temperature controlled spacings of the emitter and collector. Reproducible spacing of 10 microns (0.4 mils) were achieved on several converters. This paper presents details of SAVTEC converter construction and performance, including volt-ampere curves.

  8. Catalytic converter with thermoelectric generator

    SciTech Connect (OSTI)

    Parise, R.J.

    1998-07-01T23:59:59.000Z

    The unique design of an electrically heated catalyst (EHC) and the inclusion of an ECO valve in the exhaust of an internal combustion engine will meet the strict new emission requirements, especially at vehicle cold start, adopted by several states in this country as well as in Europe and Japan. The catalytic converter (CC) has been a most useful tool in pollution abatement for the automobile. But the emission requirements are becoming more stringent and, along with other improvements, the CC must be improved to meet these new standards. Coupled with the ECO valve, the EHC can meet these new emission limits. In an internal combustion engine vehicle (ICEV), approximately 80% of the energy consumed leaves the vehicle as waste heat: out the tail pipe, through the radiator, or convected/radiated off the engine. Included with the waste heat out the tail pipe are the products of combustion which must meet strict emission requirements. The design of a new CC is presented here. This is an automobile CC that has the capability of producing electrical power and reducing the quantity of emissions at vehicle cold start, the Thermoelectric Catalytic Power Generator. The CC utilizes the energy of the exothermic reactions that take place in the catalysis substrate to produce electrical energy with a thermoelectric generator. On vehicle cold start, the thermoelectric generator is used as a heat pump to heat the catalyst substrate to reduce the time to catalyst light-off. Thus an electrically heated catalyst (EHC) will be used to augment the abatement of tail pipe emissions. Included with the EHC in the exhaust stream of the automobile is the ECO valve. This valve restricts the flow of pollutants out the tail pipe of the vehicle for a specified amount of time until the EHC comes up to operating temperature. Then the ECO valve opens and allows the full exhaust, now treated by the EHC, to leave the vehicle.

  9. Continuum resonance induced electromagnetic torque by a rotating plasma response to static resonant magnetic perturbation field

    SciTech Connect (OSTI)

    Liu Yueqiang; Connor, J. W.; Cowley, S. C.; Ham, C. J.; Hastie, R. J.; Hender, T. C. [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom)

    2012-10-15T23:59:59.000Z

    A numerical study is carried out, based on a simple toroidal tokamak equilibrium, to demonstrate the radial re-distribution of the electromagnetic torque density, as a result of a rotating resistive plasma (linear) response to a static resonant magnetic perturbation field. The computed electromagnetic torque peaks at several radial locations even in the presence of a single rational surface, due to resonances between the rotating response, in the plasma frame, and both Alfven and sound continuum waves. These peaks tend to merge together to form a rather global torque distribution, when the plasma resistivity is large. The continuum resonance induced net electromagnetic torque remains finite even in the limit of an ideal plasma.

  10. Concentric ring flywheel with hooked ring carbon fiber separator/torque coupler

    DOE Patents [OSTI]

    Kuklo, Thomas C. (Oakdale, CA)

    1999-01-01T23:59:59.000Z

    A concentric ring flywheel with expandable separators, which function as torque couplers, between the rings to take up the gap formed between adjacent rings due to differential expansion between different radius rings during rotation of the flywheel. The expandable separators or torque couplers include a hook-like section at an upper end which is positioned over an inner ring and a shelf-like or flange section at a lower end onto which the next adjacent outer ring is positioned. As the concentric rings are rotated the gap formed by the differential expansion there between is partially taken up by the expandable separators or torque couplers to maintain torque and centering attachment of the concentric rings.

  11. Concentric ring flywheel with hooked ring carbon fiber separator/torque coupler

    DOE Patents [OSTI]

    Kuklo, T.C.

    1999-07-20T23:59:59.000Z

    A concentric ring flywheel with expandable separators, which function as torque couplers, between the rings to take up the gap formed between adjacent rings due to differential expansion between different radius rings during rotation of the flywheel. The expandable separators or torque couplers include a hook-like section at an upper end which is positioned over an inner ring and a shelf-like or flange section at a lower end onto which the next adjacent outer ring is positioned. As the concentric rings are rotated the gap formed by the differential expansion there between is partially taken up by the expandable separators or torque couplers to maintain torque and centering attachment of the concentric rings. 2 figs.

  12. Using min-max of torque to resolve redundancy for a mobile manipulator

    SciTech Connect (OSTI)

    Reister, D.B.

    1993-11-01T23:59:59.000Z

    We have considered the problem of determining the time trajectories of the joint variables of a mobile manipulator with many redundant degrees of freedom that will minimize the maximum value of the torque during a large scale motion by the manipulator. To create a well defined problem, we will divide the problem into two components: path planner and surveyor. The path planner will choose a path (between two points in Cartesian space) that will minimize the maximum value of the torque along the path. The input to the path planner is a network of path segments with the maximum value of the torque on each segment. The surveyor will find the points in joint space that are local minimums for the maximum value of the torque at each Cartesian position and define the network of path segments. In this paper, our focus will be on the surveyor and not on the path planner. Our min-max problem has an extra constraint on the joint variables. We seek a min-max at each Cartesian position rather than a global min-max. We have used the Kuhn-Tucker conditions to derive necessary conditions for the solution of our min-max problem. We find that the necessary conditions require that at one or more of the joints the magnitude of the normalized torques will be equal to the min-max value. We have explored the torque surfaces for two mobile manipulators: a planar manipulator and the CESARm. The CESARm is a manipulator with three joint angles controlling the height of the arm. The paths with three equal torques have low values for the torque but they only cover part of the workspace and do not join together. Paths with two equal torques cover the workspace and bridge between the disjoint path segments. We have evaluated the necessary conditions for both the paths with three equal torques and the paths with two equal torques. In most cases, the paths satisfy the necessary conditions.

  13. Monitoring MWD torque improved pdc bit penetration rates

    SciTech Connect (OSTI)

    Koskie, E.T. Jr. (Diamant Boart, Stratabit, Houston, TX (US)); Slagel, P. (Anadrill Schlumberger, New Orleans, LA (US)); Lesso, W. Jr. (Anadrill Schlumberger, Sugar Land, TX (US))

    1988-10-01T23:59:59.000Z

    Measurement while drilling tools were used to monitor and adjust downhole torque, which resulted in faster drilling and longer bit life. Polycrystalline diamond compact (PDC) bits have changed drilling strategies in the sand shale sequences of the Gulf of Mexico, increasing both rate of penetration and bit run lengths, and decreasing drilling costs, particularly in directional wells. While these important results have been achieved using the best drilling information available, little attention has been paid to downhole operating conditions since this information was unavailable during realtime drilling operations. In an effort to learn what benefits could be realized through applying MWD drilling technology to directional drilling with PDC bits, Tenneco teamed up with Anadrill Schlumberger for MWD downhole drilling measurements, and Diamant Boart Stratabit with their PD-11 series bits, to see what could be gained by the close cooperation of these three parties in drilling a typical offshore well. The result was a well drilled on target and under budget, and a new record bit run.

  14. Method and apparatus for monitoring motor operated valve motor output torque and power at valve seating

    DOE Patents [OSTI]

    Casada, Donald A. (Oak Ridge, TN)

    1996-01-01T23:59:59.000Z

    A method and apparatus are provided for monitoring a motor operated valve during the brief period when the valve seats and the torque switch trips to deenergize the valve motor. The method uses voltage measurements on the load side of a deenergizing switch that opens to deenergize the motor to determine, among other things, final motor rotational speed and the decelerating torque at motor deenergization.

  15. A variable parameter thermionic energy converter

    E-Print Network [OSTI]

    Bragg, Bobby Joe

    1967-01-01T23:59:59.000Z

    Point Spacing Figure~ Power Jersus Spacing Wit?&out 'inmmum Power Point CHAPTER III THEORY OF OPERATION Brief History Vacuum diodes. The earliest known analysis and testing of therm- ionic energy converters was made on vacuum converters (i. e.... , a converter in which the interelectrode space is highly evacuated) by W. Schlicter in 1915 (2). He built a vacuum diode with a platinum emitter at 1000 0 yielding 1. 5 x 10 watt with an efficiency of about 10 $. These results, plus his analysis...

  16. Perpendicular spin transfer torque magnetic random access memories with high spin torque efficiency and thermal stability for embedded applications (invited)

    SciTech Connect (OSTI)

    Thomas, Luc, E-mail: luc.thomas@headway.com; Jan, Guenole; Zhu, Jian; Liu, Huanlong; Lee, Yuan-Jen; Le, Son; Tong, Ru-Ying; Pi, Keyu; Wang, Yu-Jen; Shen, Dongna; He, Renren; Haq, Jesmin; Teng, Jeffrey; Lam, Vinh; Huang, Kenlin; Zhong, Tom; Torng, Terry; Wang, Po-Kang [TDK-Headway Technologies, Inc., Milpitas, California 95035 (United States)

    2014-05-07T23:59:59.000Z

    Magnetic random access memories based on the spin transfer torque phenomenon (STT-MRAMs) have become one of the leading candidates for next generation memory applications. Among the many attractive features of this technology are its potential for high speed and endurance, read signal margin, low power consumption, scalability, and non-volatility. In this paper, we discuss our recent results on perpendicular STT-MRAM stack designs that show STT efficiency higher than 5?k{sub B}T/?A, energy barriers higher than 100?k{sub B}T at room temperature for sub-40?nm diameter devices, and tunnel magnetoresistance higher than 150%. We use both single device data and results from 8?Mb array to demonstrate data retention sufficient for automotive applications. Moreover, we also demonstrate for the first time thermal stability up to 400?C exceeding the requirement of Si CMOS back-end processing, thus opening the realm of non-volatile embedded memory to STT-MRAM technology.

  17. New Perspectives on Wave Energy Converter Control

    E-Print Network [OSTI]

    Price, Alexandra A E

    2009-01-01T23:59:59.000Z

    This work examines some of the fundamental problems behind the control of wave energy converters (WECs). Several new perspectives are presented to aid the understanding of the problem and the interpretation of the ...

  18. Improved Low-Temperature Performance of Catalytic Converters...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Catalytic converters, installed on vehicles with internal combustion and diesel engines, convert the toxic byproducts of combustion to less toxic compounds. In two-way (lean...

  19. acid residues converted: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Websites Summary: - Resonant converters and related systems, such as piezoelectric transformers, may require a high of resonant converters: a series-resonant parallel-...

  20. ars projekt converted: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Websites Summary: - Resonant converters and related systems, such as piezoelectric transformers, may require a high of resonant converters: a series-resonant parallel-...

  1. angiotensin converting enzyme-3: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Websites Summary: - Resonant converters and related systems, such as piezoelectric transformers, may require a high of resonant converters: a series-resonant parallel-...

  2. angiotensin converting enzyme: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Websites Summary: - Resonant converters and related systems, such as piezoelectric transformers, may require a high of resonant converters: a series-resonant parallel-...

  3. SEP Success Story: State Energy Program Helping Arkansans Convert...

    Energy Savers [EERE]

    State Energy Program Helping Arkansans Convert to Compressed Natural Gas SEP Success Story: State Energy Program Helping Arkansans Convert to Compressed Natural Gas January 25,...

  4. Enterprise converting buses to biodiesel | Department of Energy

    Energy Savers [EERE]

    Enterprise converting buses to biodiesel Enterprise converting buses to biodiesel April 1, 2010 - 6:48pm Addthis Paul Lester Communications Specialist, Office of Energy Efficiency...

  5. Power Losses Estimation Platform for Power Songquan Deng, Hong Mao, Tomas Wu, Shangyang Xiao and Issa Batarseh

    E-Print Network [OSTI]

    Wu, Shin-Tson

    Power Losses Estimation Platform for Power Converters Songquan Deng, Hong Mao, Tomas Wu, Shangyang Orlando, FL 32816, USA dengsongquan@hotmail.com Abstract- A power losses analysis platform integrating powerful analysis software PspiceTM , MathCADTM and MaxwellTM capable of calculating losses on the key

  6. Utilizing zero-sequence switchings for reversible converters

    DOE Patents [OSTI]

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

    2004-12-14T23:59:59.000Z

    A method for providing additional dc inputs or outputs (49, 59) from a dc-to-ac inverter (10) for controlling motor loads (60) comprises deriving zero-sequence components (V.sub.ao, V.sub.bo, and V.sub.co) from the inverter (10) through additional circuit branches with power switching devices (23, 44, 46), transforming the voltage between a high voltage and a low voltage using a transformer or motor (42, 50), converting the low voltage between ac and dc using a rectifier (41, 51) or an H-bridge (61), and providing at least one low voltage dc input or output (49, 59). The transformation of the ac voltage may be either single phase or three phase. Where less than a 100% duty cycle is acceptable, a two-phase modulation of the switching signals controlling the inverter (10) reduces switching losses in the inverter (10). A plurality of circuits for carrying out the invention are also disclosed.

  7. Evaluating Transformer Losses

    E-Print Network [OSTI]

    Grun, R. L. Jr.

    therefore are a function of the load squared. No-load losses occur from energizing the transformer steel and fore are continuous regardless of the transformer load. TRANSFORMER DESIGN Both types of losses are a fun ce here ion of design. If losses...

  8. Isolated and soft-switched power converter

    DOE Patents [OSTI]

    Peng, Fang Zheng (Knoxville, TN); Adams, Donald Joe (Knoxville, TN)

    2002-01-01T23:59:59.000Z

    An isolated and soft-switched power converter is used for DC/DC and DC/DC/AC power conversion. The power converter includes two resonant tank circuits coupled back-to-back through an isolation transformer. Each resonant tank circuit includes a pair of resonant capacitors connected in series as a resonant leg, a pair of tank capacitors connected in series as a tank leg, and a pair of switching devices with anti-parallel clamping diodes coupled in series as resonant switches and clamping devices for the resonant leg. The power converter is well suited for DC/DC and DC/DC/AC power conversion applications in which high-voltage isolation, DC to DC voltage boost, bidirectional power flow, and a minimal number of conventional switching components are important design objectives. For example, the power converter is especially well suited to electric vehicle applications and load-side electric generation and storage systems, and other applications in which these objectives are important. The power converter may be used for many different applications, including electric vehicles, hybrid combustion/electric vehicles, fuel-cell powered vehicles with low-voltage starting, remote power sources utilizing low-voltage DC power sources, such as photovoltaics and others, electric power backup systems, and load-side electric storage and generation systems.

  9. Stressing of turbine-generator-exciter shafts by variable-frequency currents superimposed on DC currents in asynchronous HVDC links and following disturbances at converter stations

    SciTech Connect (OSTI)

    Hammons, T.J.; Bremner, J.J. (Univ. of Glasgow (United Kingdom))

    1994-09-01T23:59:59.000Z

    Ripple currents on the DC side of both HVDC synchronous and asynchronous. Links together with cleared HVDC and AC system disturbances can excite in some circumstances onerous torsional vibrations in large steam generator shafts. The problem has assumed importance in recent months on account of the HVDC Link between Scotland and Northern Ireland going ahead, on account of the proposed Eire/Wales Link, and because AC/DC/AC couplers are to be installed extensively to interconnect the East and West European Grid Systems. This paper discusses and analyses excitation of shaft torsional vibrations in steam turbine-generator-exciter shafts in close proximity to HVDC converter stations by (1) variable-frequency ripple currents superimposed on the DC currents in asynchronous Links, and (2) disturbances at bi-polar converter stations. The time response and tables show that for the systems studied variable-frequency ripple currents superimposed on the DC current in asynchronous Links can excite shaft torsional vibrations, the very small noncharacteristic currents could result in onerous shaft torques which might damage the machine, and that DC line faults at converter stations in close proximity of steam turbine-generator units can excite onerous turbine-generator shaft torsional response. Detailed simulation of the HVDC converter and generator is necessary for precise assessments of shaft torsional response following HVDC converter station faults. 500MW, 660MW, 1000MW and 1300MW machines are considered in the analyses that are made.

  10. Thermally activated switching of perpendicular magnet by spin-orbit spin torque

    SciTech Connect (OSTI)

    Lee, Ki-Seung [Department of Materials Science and Engineering, Korea University, Seoul 136-701 (Korea, Republic of); Spin Convergence Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Lee, Seo-Won [Department of Materials Science and Engineering, Korea University, Seoul 136-701 (Korea, Republic of); Min, Byoung-Chul [Spin Convergence Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Lee, Kyung-Jin, E-mail: kj-lee@korea.ac.kr [Department of Materials Science and Engineering, Korea University, Seoul 136-701 (Korea, Republic of); Spin Convergence Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 136-713 (Korea, Republic of)

    2014-02-17T23:59:59.000Z

    We theoretically investigate the threshold current for thermally activated switching of a perpendicular magnet by spin-orbit spin torque. Based on the Fokker-Planck equation, we obtain an analytic expression of the switching current, in agreement with numerical result. We find that thermal energy barrier exhibits a quasi-linear dependence on the current, resulting in an almost linear dependence of switching current on the log-scaled current pulse-width even below 10?ns. This is in stark contrast to standard spin torque switching, where thermal energy barrier has a quadratic dependence on the current and the switching current rapidly increases at short pulses. Our results will serve as a guideline to design and interpret switching experiments based on spin-orbit spin torque.

  11. Adaptive external torque estimation by means of tracking a Lyapunov function

    SciTech Connect (OSTI)

    Schaub, H.; Junkins, J.L. [Texas A and M Univ., College Station, TX (United States); Robinett, R.D. [Sandia National Labs., Albuquerque, NM (United States)

    1996-03-01T23:59:59.000Z

    A real-time method is presented to adoptively estimate three-dimensional unmodeled external torques acting on a spacecraft. This is accomplished by forcing the tracking error dynamics to follow the Lyapunov function underlying the feedback control law. For the case where the external torque is constant, the tracking error dynamics are shown to converge asypmtotically. The methodology applies not only to the control law used in this paper, but can also be applied to most Lyapunov derived feedback control laws. The adaptive external torque estimation is very robust in the presence of measurement noise, since a numerical integration is used instead of a numerical differentiation. Spacecraft modeling errors, such as in the inertia matrix, are also compensated for by this method. Several examples illustrate the practical significance of these ideas.

  12. Power and Torque Characteristics of Diesel Engine Fuelled by Palm-Kernel Oil Biodiesel

    E-Print Network [OSTI]

    Oguntola J Alamu; Ezra A Adeleke; Nurudeen O. Adekunle; Salam O; Oguntola J Alamu; Ezra A Adeleke; Nurudeen O Adekunle; Salam O Ismaila

    Short-term engine performance tests were carried out on test diesel engine fuelled with Palm kernel oil (PKO) biodiesel. The biodiesel fuel was produced through transesterification process using 100g PKO, 20.0 % ethanol (wt%), 1.0 % potassium hydroxide catalyst at 60C reaction temperature and 90min. reaction time. The diesel engine was attached to a general electric dynamometer. Torque and power delivered by the engine were monitored throughout the 24-hour test duration at 1300, 1500, 1700, 2000, 2250 and 2500rpm. At all engine speeds tested, results showed that torque and power outputs for PKO biodiesel were generally lower than those for petroleum diesel. Also, Peak torque for PKO biodiesel occurred at a lower engine speed compared to diesel.

  13. External ionization mechanisms for advanced thermionic converters

    SciTech Connect (OSTI)

    Hatziprokopiou, M.E.

    1981-01-01T23:59:59.000Z

    This work investigates ion generation and recombination mechanisms in the cesium plasma as they pertain to the advanced mode thermionic energy converter. The changes in plasma density and temperature within the converter have been studied under the influence of several promising auxiliary ionization candidate sources. Three novel approaches of external cesium ion generation have been investigated in some detail, namely vibrationally excited N/sub 2/ as are energy source of ionization of Cs ions in a dc discharge, microwave power as a means of resonant sustenance of the cesium plasma, and ion generation in a pulse N/sub 2/-Cs mixture. The experimental data obtained and discussed in this work show that all three techniques - i.e. the non-LTE high-voltage pulsing, the energy transfer from vibrationally excited diatomic gases, and the external pumping with a microwave power - have considerable promise as schemes in auxiliary ion generation applicable to the advanced thermionic energy converter.

  14. Optimum torque determination and selection of rotary shouldered drill collar connections

    E-Print Network [OSTI]

    Marlow, Roy Stone

    1972-01-01T23:59:59.000Z

    vs. bending moment, 4 1/2 in. I'H. 72 Figure Page 34 Longitudinal stress (gages 1 to 9) vs. torque, 5 in. H-90. 73 35 I. ongitud. inal bending stress (gages 1 & 2) vs. bending moment, 5 in. H-90. 74 36 Longitudinal bending stress (gages 3 to 9...) vs, bending moment, 5 in. H ? 90. 75 37 Deflection at center vs. bending moment, 5 in. H-90. 76 38 Longitudinal stress (gages 1 to 9) vs. torque, 5 in. XH. 77 39 Longitudinal bending stress (gages 1 & 2) vs. bending moment, 5 in. XH. 78 40...

  15. Local spin torque induced by electron electric dipole moment in the YbF molecule

    SciTech Connect (OSTI)

    Fukuda, Masahiro; Senami, Masato; Ogiso, Yoji; Tachibana, Akitomo [Department of Micro Engineering, Kyoto University, Kyoto 615-8540 (Japan)

    2014-10-06T23:59:59.000Z

    In this study, we show the modification of the equation of motion of the electronic spin, which is derived by the quantum electron spin vorticity principle, by the effect of the electron electric dipole moment (EDM). To investigate the new contribution to spin torque by EDM, using first principle calculations, we visualize distributions of the local spin angular momentum density and local spin torque density of the YbF molecule on which the static electric field and magnetic field are applied at t = 0.

  16. Zero field high frequency oscillations in dual free layer spin torque oscillators

    SciTech Connect (OSTI)

    Braganca, P. M., E-mail: patrick.braganca@hgst.com; Pi, K.; Zakai, R.; Childress, J. R.; Gurney, B. A. [HGST, 3404 Yerba Buena Rd., San Jose, California 95135 (United States)] [HGST, 3404 Yerba Buena Rd., San Jose, California 95135 (United States)

    2013-12-02T23:59:59.000Z

    We observe microwave oscillations in relatively simple spin valve spin torque oscillators consisting of two in-plane free layers without spin polarizing layers. These devices exhibit two distinct modes which can reach frequencies >25?GHz in the absence of an applied magnetic field. Macrospin simulations identify these two modes as optical and acoustic modes excited by the coupling of the two layers through dipole field and spin torque effects. These results demonstrate the potential of this system as a large output power, ultrahigh frequency signal generator that can operate without magnetic field.

  17. Modeling torque versus speed, shot noise, and rotational diffusion of the bacterial flagellar motor

    E-Print Network [OSTI]

    Thierry Mora; Howard Yu; Ned S. Wingreen

    2009-10-05T23:59:59.000Z

    We present a minimal physical model for the flagellar motor that enables bacteria to swim. Our model explains the experimentally measured torque-speed relationship of the proton-driven E. coli motor at various pH and temperature conditions. In particular, the dramatic drop of torque at high rotation speeds (the "knee") is shown to arise from saturation of the proton flux. Moreover, we show that shot noise in the proton current dominates the diffusion of motor rotation at low loads. This suggests a new way to probe the discreteness of the energy source, analogous to measurements of charge quantization in superconducting tunnel junctions.

  18. Characteristics of two thermionic converters with oxide collectors

    SciTech Connect (OSTI)

    Smith, E.A.; Huffman, F.N.

    1984-08-01T23:59:59.000Z

    Thermionic converters built with selected metal oxide coatings on their collectors have given enhanced performance at interelectrode spacings greater than 0.25 mm. The capability of such converters to operate efficiently at large interelectrode spacings is of interest for in-core thermionic power systems. Performance data are reported from one converter built with a collector having a coating of molybdenum sublimed in oxygen and a second converter containing an oxidized zirconium collector. The molybdenum oxide collector converter demonstrated enhanced performance.

  19. IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS, VOL. 35, NO. 2, MARCH/APRIL 1999 461 Torque-Ripple Minimization in Switched

    E-Print Network [OSTI]

    Husain, Iqbal

    , General Motors Research and Development Center, Warren, MI 48090 USA. M. E. Elbuluk and I. Husain-Ripple Minimization in Switched Reluctance Motors Using Adaptive Fuzzy Control S. ayeed Mir, Member, IEEE, Malik E up to the motor base speed. The torque is generated over the maximum positive torque-producing region

  20. IEEE TRANSACTIONS ON CONTROL SYSTEMS TECHNOLOGY, VOL. 7, NO. 5, SEPTEMBER 1999 555 Analysis and Control of Transient Torque Response

    E-Print Network [OSTI]

    Stefanopoulou, Anna

    the formation of oxides of nitrogen (NO ) in internal combustion engines and thus reduce one of the main and Control of Transient Torque Response in Engines with Internal Exhaust Gas Recirculation Anna G--Dynamic response, emissions, internal combus- tion engines, poles and zeros, pollution control, modeling, torque

  1. On the force and torque on systems of rigid bodies: A remark on an integral formula due to Howe

    E-Print Network [OSTI]

    Tabak, Esteban G.

    On the force and torque on systems of rigid bodies: A remark on an integral formula due to Howe 2007 M. S. Howe J. Fluid Mech. 206, 131 1989 presented integral formulas for the force and torque induced by free vorticity, and viscous skin friction. Here a simple extension of Howe's formulas is done

  2. Real-Time Combustion Torque Estimation on a Diesel Engine Test Bench Using Time-Varying Kalman Filtering

    E-Print Network [OSTI]

    Real-Time Combustion Torque Estimation on a Diesel Engine Test Bench Using Time-Varying Kalman sensor the easily available instantaneous crankshaft angle speed. The observer consists in a Kalman torque observer, we use a physics-based model underlying the role of time-varying inertia. A Kalman

  3. Safe Reaction of a Robot Arm with Torque Sensing Ability on the External Disturbance and Impact: Implementation of a New

    E-Print Network [OSTI]

    Tachi, Susumu

    Safe Reaction of a Robot Arm with Torque Sensing Ability on the External Disturbance and Impact anthropomorphic robot arm enabling the torque measurement in each joint to ensure safety while performing tasks control imparting reflex action ability to the robot arm was proposed. The experimental results showed

  4. Abstract--This paper proposes a new approach to the prediction of the cogging torque in motors with parallel or

    E-Print Network [OSTI]

    Lu, Kaiyuan

    vibration and acoustic noise. Cogging torque is produced by the interaction of the permanent magnets382 Abstract--This paper proposes a new approach to the prediction of the cogging torque in motors motors. I. INTRODUCTION ERMANENT magnet (PM) motors have been widely used in high performance

  5. IEEE TRANSACTIONS ON ENERGY CONVERSION, VOL. 17, NO. 2, JUNE 2002 169 Control-Based Reduction of Pulsating Torque

    E-Print Network [OSTI]

    Stankoviæ, Aleksandar

    and cogging torque with zero mean value and produces only vibration and acoustic noise, which may be even reduction for surface-mounted permanent magnet motors are discussed in this paper. The pulsating torque motor speed using the internal model principle and adaptive feedforward compensation technique

  6. Switched-Mode Power Converter Programmable

    E-Print Network [OSTI]

    -line identification of converter dynamic responses [2, 5, 6], tuning of controller parameters based on identification dynamics followed by an automated algorithm to derive a controller design to meet a desired closed performance controller, an accurate parametric model is necessary. Particularly, a Z-domain transfer function

  7. Converting Centrifugal Chillers to HCFC-123

    E-Print Network [OSTI]

    Siebert, B.

    1994-01-01T23:59:59.000Z

    of large water chillers in addressing the CFC issue. These owners, for a variety of reasons, chose to address the issue through the conversion of the existing equipment to an HCFC refrigerant. For each of the three owners, the option of converting...

  8. Combustion converter development for topping and cogeneration applications

    SciTech Connect (OSTI)

    Goodale, D.; Lieb, D.; Miskolczy, G.; Moffat, A.

    1983-08-01T23:59:59.000Z

    This paper discusses the development of combustion-heated thermionic converters. Combustion applications pose a materials problem that does not exist for thermionic converters used in the vacuum of outer space. The high-temperature components of a thermionic converter must be protected from the oxidizing terrestrial environment. A layer of silicon carbide provides the most satisfactory protective coating, or ''hot shell,'' for the emitter and lead of a combustion-heated thermionic converter. Four areas of work aimed at developing combustion heated thermionic converters will be discussed: improving the performance of the two-inch torispherical converter, modifications to the converter so that it may be used in multi-converter modules, the construction of a thermionic cogeneration test furnace, and a converter life test in an oil-fired furnace.

  9. Role of friction-induced torque in stick-slip motion J. Scheibert1,

    E-Print Network [OSTI]

    Role of friction-induced torque in stick-slip motion J. Scheibert1, and D.K. Dysthe1 1 PGP describing the kinematics of the transition from static friction to stick-slip motion of a linear elastic the precursors to frictional sliding and the periodic stick- slip motion are controlled by the amount of friction

  10. Oscillation annealing and driver/tire load torque estimation in Electric Power Steering Systems

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    the improved LuGre-tire friction model. Index Terms-- Electric Power Steering systems (EPSs), LQ control, Lu a control framework that includes a realistic model of a steering column accounting for all other torque. The contributions of this paper are: a) Optimal output control feedback: Based on the steer- ing column model

  11. Achieving Consistent Maximum Brake Torque with Varied Injection Timing in a DI Diesel Engine

    E-Print Network [OSTI]

    Kroeger, Timothy H

    2013-09-19T23:59:59.000Z

    The brake torque of a direct-injection diesel engine is known to plateau over a range of injection timings. Injection timing affects the engines ignition delay and the fractions of fuel which burn in premixed and diffusion modes. Therefore...

  12. Electric Vehicle Induction Motor DSVM-DTC with Torque Ripple Minimization

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    Electric Vehicle Induction Motor DSVM-DTC with Torque Ripple Minimization Farid Khoucha1 a sensorless DSVM-DTC of an induction motor that propels an electrical vehicle or a hybrid one. The drive uses, as demonstrated in experimental results. Keywords: Electric vehicle (EV), induction motor, Discrete Space Vector

  13. Passive torque wrench and angular position detection using a single-beam optical trap

    E-Print Network [OSTI]

    Wang, Michelle

    Passive torque wrench and angular position detection using a single-beam optical trap James Inman,1 August 26, 2010 The recent advent of angular optical trapping techniques has allowed for rotational torsional measurements across a wide range of biological systems. 2010 Optical Society of America OCIS

  14. Torque-generating malaria-infected red blood cells in an optical trap

    E-Print Network [OSTI]

    Sharma, Shobhona

    Torque-generating malaria-infected red blood cells in an optical trap J.A. Dharmadhikari, S. Roy, A 005, India # atmol1@tifr.res.in Abstract: We have used optical tweezers to trap normal and Plasmodium emerge from our experiments. Firstly, while the optical field modifies both types of RBCs in the same

  15. An Ankle-Foot Prosthesis Emulator with Control of Plantarflexion and Inversion-Eversion Torques

    E-Print Network [OSTI]

    Collins, Steven H.

    An Ankle-Foot Prosthesis Emulator with Control of Plantarflexion and Inversion-Eversion Torques-foot prosthesis with two independently-actuated toes that are coordinated to provide plantarflexion and inversion prosthesis features. A similar morphology may be effective for autonomous devices. I. INTRODUCTION Robotic

  16. Tightening force and torque of nonlocking screws in a reverse shoulder prosthesis A. Terrier a,

    E-Print Network [OSTI]

    Guerraoui, Rachid

    Tightening force and torque of nonlocking screws in a reverse shoulder prosthesis A. Terrier a, , S Arthroplasty Reversed prosthesis Screw Cadaveric study Background: Reversed shoulder arthroplasty and screwing angle, of the nonlocking screws of the Aquealis reversed prosthesis. In addition, the amount

  17. Proton transport and torque generation in rotary biomotors A. Yu. Smirnov,1

    E-Print Network [OSTI]

    Nori, Franco

    nanoelectromechanical model, consisting of a stator part and a ring-shaped rotor having 12 proton-binding sites and the positive stator charge, located near the periplasmic proton-conducting channel proton source , plays a dominant role in the torque-generating process. When approaching the source outlet, the rotor site has

  18. Technical Section Evaluating the influence of induced passive torques in the

    E-Print Network [OSTI]

    Rodrguez, Inmaculada

    Accepted 15 June 2008 Keywords: Animation Human poses Joint fatigue assessment Passive torques Virtual, such as computer animation, virtual reality and ergonomics, there is a need to generate realistic human postures-varying human poses I. Rodriguez a,,1 , R. Boulic b a Applied Mathematics Department, Universitat de Barcelona

  19. Efficient High-speed Vision-based Computed Torque Control of the Orthoglide Parallel Robot

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    , without any joint sensing, by a novel Cartesian pose and velocity estimator. The latter is designed robot (or parallel kinematic manipulator) control is the Cartesian space. The main reason torque control consists in how to obtain the robot Cartesian pose x and its time derivative x. The two

  20. Optimal Design of Motor and Gear for Drives with High Acceleration and Load Torque

    E-Print Network [OSTI]

    Paderborn, Universitt

    Optimal Design of Motor and Gear for Drives with High Acceleration and Load Torque H. Grotstollen-acceleration product are transmitted unchanged by an ideal gear. At a first step those motors can be selected which offer sufficient rated power and power rate. When designing gears for each of these motors two ranges

  1. Unknown: Multifocal scalp hair loss

    E-Print Network [OSTI]

    Shamsadini, Sadollah; Esfandiarpoor, Iraj; Zeinali, Hamid; Kalantari, Behjat; Ebrahimi, Hoseiali

    2006-01-01T23:59:59.000Z

    Unknown: Multifocal scalp hair loss Sadllah Shamsadini 1 ,four patches of scalp hair loss. What is your diagnosis?

  2. A square root analog to digital converter to optimally convert photonic signals for computed tomography

    E-Print Network [OSTI]

    Bieniosek, Matthew (Matthew F.)

    2010-01-01T23:59:59.000Z

    The arrival of photons at a given location is a Poisson process with an associated shot noise which rises with the square root of the number of photons received. An analog-to-digital converter (ADC) with a square root ...

  3. Calibration of the optical torque wrench Francesco Pedaci,1,2 Zhuangxiong Huang,1,2 Maarten van Oene,1 and

    E-Print Network [OSTI]

    Dekker, Nynke

    Calibration of the optical torque wrench Francesco Pedaci,1,2 Zhuangxiong Huang,1,2 Maarten van-first authors *n.h.dekker@tudelft.nl Abstract: The optical torque wrench is a laser trapping technique that expands the capability of standard optical tweezers to torque manipulation and measurement, using

  4. This article has been accepted for publication in a future issue of this journal, but has not been fully edited. Content may change prior to final publication. Abstract--Asymmetric multilevel converters can optimize the

    E-Print Network [OSTI]

    Catholic University of Chile (Universidad Catlica de Chile)

    fuel cells in a hospital or where a failure may cost thousands of dollars of losses. The topology converters can optimize the number of levels by using H bridges scaled in power of three. The shortcoming

  5. Evolution of binary black holes in self gravitating discs: dissecting the torques

    E-Print Network [OSTI]

    Constanze Roedig; Alberto Sesana; Massimo Dotti; Jorge Cuadra; Pau Amaro-Seoane; Francesco Haardt

    2012-08-14T23:59:59.000Z

    We study the interplay between gas accretion and gravity torques in changing a binary elements and its total angular momentum (L) budget. Especially, we analyse the physical origin of the gravity torques (T_g) and their location within the disc. We analyse 3D SPH simulations of the evolution of initially quasi-circular massive black hole binaries (BHBs) residing in the central hollow of massive self-gravitating circumbinary discs. We use different thermodynamics within the cavity and for the numerical size of the black holes to show that (i) the BHB eccentricity growth found previously is a general result, independent of the accretion and the adopted thermodynamics; (ii) the semi-major axis decay depends both on the T_g and on the interplay with the disc-binary L-transfer due to accretion; (iii) the spectral structure of the T_g is predominately caused by disc edge overdensities and spiral arms developing in the body of the disc and, in general, does not reflect directly the period of the binary; (iv) the net T_g changes sign across the BHB corotation radius. We quantify the relative importance of the two, which appear to depend on the thermodynamical properties of the instreaming gas, and which is crucial in assessing the disc-binary L-transfer; (v) the net torque manifests as a purely kinematic (non-resonant) effect as it stems from the cavity, where the material flows in and out in highly eccentric orbits. Both accretion onto the black holes and the interaction with gas streams inside the cavity must be taken into account to assess the fate of the BHB. Moreover, the total torque exerted by the disc affects L(BHB) by changing all the elements (mass, mass ratio, eccentricity, semimajor axis) of the BHB. Common prescriptions equating tidal torque to semi-major axis shrinking might therefore be poor approximations for real astrophysical systems.

  6. An economical single to three phase converter for induction motors

    E-Print Network [OSTI]

    Di Zerega, Philp Van Uytandaele

    1994-01-01T23:59:59.000Z

    There are several different types of single to three phase converters for induction motors available today. However, many of the presently available phase converters suffer from disadvantages such as high cost or low performance. An economical...

  7. DOE Announces Webinars on the Wave Energy Converter Prize, the...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    DOE Announces Webinars on the Wave Energy Converter Prize, the Best of the Clean Cities Tools and Resources, and More DOE Announces Webinars on the Wave Energy Converter Prize, the...

  8. Automated Synthesis Tool for Design Optimization of Power Electronic Converters

    E-Print Network [OSTI]

    Mirjafari, Mehran

    2013-01-09T23:59:59.000Z

    module-integrated photovoltaic inverter is also optimized for efficiency, volume and reliability. An actual converter is constructed using commercial off-the-shelf components. The converter design is chosen as close as possible to a point obtained...

  9. An economical single to three phase converter for induction motors

    E-Print Network [OSTI]

    Di Zerega, Philp Van Uytandaele

    1994-01-01T23:59:59.000Z

    There are several different types of single to three phase converters for induction motors available today. However, many of the presently available phase converters suffer from disadvantages such as high cost or low performance. An economical...

  10. Digital radix converters for high accuracy data conversion

    E-Print Network [OSTI]

    Ghanta, Venkataratnam Chowdary

    1993-01-01T23:59:59.000Z

    A sub-binary radix Digital to Analog converter(DAC) which achieves high effective resolution is demonstrated. The converter does not have any built-in-self calibration mechanisms, but achieves high resolution and accuracy through the sub...

  11. Heat Pump Water Heater using Solid-State Energy Converters |...

    Energy Savers [EERE]

    Heat Pump Water Heater using Solid-State Energy Converters Heat Pump Water Heater using Solid-State Energy Converters Sheetak will work on developing a full scale prototype of its...

  12. A low-power reconfigurable analog-to-digital converter

    E-Print Network [OSTI]

    Gulati, Kush

    2001-01-01T23:59:59.000Z

    This thesis presents the concept, theory and design of a low power CMOS analog-to-digital converter that can digitize signals over a wide range of bandwidth and resolution with adaptive power consumption. The converter ...

  13. A transient model for a cesium vapor thermionic converter. [Cs

    SciTech Connect (OSTI)

    El-Genk, M.S.; Murray, C.S.; Chaudhuri, S. (Institute for Space Nuclear Power Studies, Department of Chemical and Nuclear Engineering, The University of New Mexico, Albuquerque, New Mexico (USA))

    1991-01-10T23:59:59.000Z

    This paper presents an analytical model for simulating the transient and steady-state operation of cesium vapor thermionic converters. A parametric analysis is performed to assess the transient response of the converter to changes in fission power and width of interelectrode gap. The model optimizes the converter performance for maximum electric power to the load.(AIP)

  14. Modelling and geometry optimisation of wave energy converters

    E-Print Network [OSTI]

    Nrvg, Kjetil

    Modelling and geometry optimisation of wave energy converters Adi Kurniawan Supervisors: Prof;Research questions Modelling How to develop more realistic wave energy converter (WEC) models while wave energy converter (WEC) models while at the same time reduce their simulation time? Optimisation

  15. Multiport Converter Topologies for Distributed Energy System Applications

    E-Print Network [OSTI]

    Hawke, Joshua

    2014-07-28T23:59:59.000Z

    technologies into singular systems, there is a growing appetite for multiport converter (MPC) design. In response, three unique DER MPC topologies are presented: the power sharing converter (PSC), the multi-level nine switch converter (ML9SC), and the modular...

  16. A Dual Supply Buck Converter with Improved Light Load Efficiency

    E-Print Network [OSTI]

    Chen, Hui

    2013-05-02T23:59:59.000Z

    ................................................................................................ 1 1.2 Thesis Organization.................................................................................................. 3 2. BACKGROUND OF BUCK CONVERTER ................................................................ 4 2.1 DC-DC Converter... ...................................................... 2 Fig. 2. 1. A basic DC-DC converter ................................................................................... 5 Fig. 2. 2. Basic topology of a close loop linear regulator................................................... 6 Fig. 2. 3...

  17. Reversal modes of exchange-spring magnets revealed by torque magnetometry.

    SciTech Connect (OSTI)

    Platt, C. L.; Berkowitz, A. E.; David, S.; Fullerton, E. E.; Jiang, J. S.; Bader, S. D.; Materials Science Division; Univ. of California; IBM Almaden Research Center

    2001-12-10T23:59:59.000Z

    Torque magnetometry measurements and related micromagnetic simulations are reported for SmCo/Fe exchange-spring films with uniaxial in-plane easy axis of magnetization. Rotating an applied magnetic field in plane, away from the easy direction, gives rise to an irreversible jump in the torque curves at a critical angle. The jump is associated with a switch in chirality of the magnetization spiral structure that develops in the magnetically soft Fe layer, pinned at the interface with the hard SmCo layer. Two reversal modes of the chirality are identified, one at low fields due to an in-plane untwisting of the spiral, and the other at high fields, due to an out-of-plane fanning of the spiral.

  18. Spin-torque diode radio-frequency detector with voltage tuned resonance

    SciTech Connect (OSTI)

    Skowro?ski, Witold, E-mail: skowron@agh.edu.pl; Frankowski, Marek; Stobiecki, Tomasz [AGH University of Science and Technology, Department of Electronics, Al. Mickiewicza 30, 30-059 Krakw (Poland); Wrona, Jerzy [AGH University of Science and Technology, Department of Electronics, Al. Mickiewicza 30, 30-059 Krakw (Poland); Singulus Technologies, Kahl am Main 63796 (Germany); Ogrodnik, Piotr [Faculty of Physics, Warsaw University of Technology, ul. Koszykowa 75, 00-662 Warsaw (Poland); AGH University of Science and Technology, Department of Electronics, Al. Mickiewicza 30, 30-059 Krakw (Poland); Barna?, Jzef [Faculty of Physics, Adam Mickiewicz University, ul. Umultowska 85, 61-614 Pozna? (Poland); Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17, 60-179 Pozna? (Poland)

    2014-08-18T23:59:59.000Z

    We report on a voltage-tunable radio-frequency (RF) detector based on a magnetic tunnel junction (MTJ). The spin-torque diode effect is used to excite and/or detect RF oscillations in the magnetic free layer of the MTJ. In order to reduce the overall in-plane magnetic anisotropy of the free layer, we take advantage of the perpendicular magnetic anisotropy at the interface between ferromagnetic and insulating layers. The applied bias voltage is shown to have a significant influence on the magnetic anisotropy, and thus on the resonance frequency of the device. This influence also depends on the voltage polarity. The obtained results are accounted for in terms of the interplay of spin-transfer-torque and voltage-controlled magnetic anisotropy effects.

  19. Spin-orbit torque magnetization switching of a three-terminal perpendicular magnetic tunnel junction

    SciTech Connect (OSTI)

    Cubukcu, Murat; Boulle, Olivier; Drouard, Marc; Mihai Miron, Ioan; Gaudin, Gilles [SPINTEC, UMR 8191, CEA/CNRS/UJF/GINP, INAC, F-38054 Grenoble (France); Garello, Kevin; Onur Avci, Can; Gambardella, Pietro [Department of Materials, ETH Zurich, Hnggerbergring 64, CH-8093 Zrich (Switzerland); Langer, Juergen; Ocker, Berthold [Singulus Technologies, Hanauer Landstr, 103, 63796 Kahl am Main (Germany)

    2014-01-27T23:59:59.000Z

    We report on the current-induced magnetization switching of a three-terminal perpendicular magnetic tunnel junction by spin-orbit torque and its read-out using the tunnelling magnetoresistance (TMR) effect. The device is composed of a perpendicular Ta/FeCoB/MgO/FeCoB stack on top of a Ta current line. The magnetization of the bottom FeCoB layer can be switched reproducibly by the injection of current pulses with density 5??10{sup 11}?A/m{sup 2} in the Ta layer in the presence of an in-plane bias magnetic field, leading to the full-scale change of the TMR signal. Our work demonstrates the proof of concept of a perpendicular spin-orbit torque magnetic memory cell.

  20. Non-linear evolution of the angular momentum of protostructures from tidal torques

    E-Print Network [OSTI]

    Paolo Catelan; Tom Theuns

    1996-04-15T23:59:59.000Z

    We discuss the non-linear evolution of the angular momentum L acquired by protostructures, like protogalaxies and protoclusters, due to tidal interactions with the surrounding matter inhomogeneities. The primordial density distribution is assumed to be Gaussian and the non-linear dynamics of the collisionless mass fluid is followed using Lagrangian perturbation theory. For a Cold Dark Matter spectrum, the inclusion of the leading-order Lagrangian correction terms results in a value of the rms ensemble average ^{1/2} which is only a factor of 1.3 higher than the corresponding linear estimate, irrespective of the scale. Consequently, the predictions of linear theory are rather accurate in quantifying the evolution of the angular momentum of protostructures before collapse sets in. In the Einstein-de Sitter universe, the initial torque is a good estimate for the tidal torque over the whole period during which the object is spun up.

  1. Voltage balanced multilevel voltage source converter system

    DOE Patents [OSTI]

    Peng, F.Z.; Lai, J.S.

    1997-07-01T23:59:59.000Z

    Disclosed is a voltage balanced multilevel converter for high power AC applications such as adjustable speed motor drives and back-to-back DC intertie of adjacent power systems. This converter provides a multilevel rectifier, a multilevel inverter, and a DC link between the rectifier and the inverter allowing voltage balancing between each of the voltage levels within the multilevel converter. The rectifier is equipped with at least one phase leg and a source input node for each of the phases. The rectifier is further equipped with a plurality of rectifier DC output nodes. The inverter is equipped with at least one phase leg and a load output node for each of the phases. The inverter is further equipped with a plurality of inverter DC input nodes. The DC link is equipped with a plurality of rectifier charging means and a plurality of inverter discharging means. The plurality of rectifier charging means are connected in series with one of the rectifier charging means disposed between and connected in an operable relationship with each adjacent pair of rectifier DC output nodes. The plurality of inverter discharging means are connected in series with one of the inverter discharging means disposed between and connected in an operable relationship with each adjacent pair of inverter DC input nodes. Each of said rectifier DC output nodes are individually electrically connected to the respective inverter DC input nodes. By this means, each of the rectifier DC output nodes and each of the inverter DC input nodes are voltage balanced by the respective charging and discharging of the rectifier charging means and the inverter discharging means. 15 figs.

  2. Solid oxygen as converter for the production of ultra-cold neutrons

    E-Print Network [OSTI]

    Frei, A; Bozhanova, R; Gutsmiedl, E; Huber, T; Klenke, J; Paul, S; Wlokka, S

    2010-01-01T23:59:59.000Z

    We have investigated solid oxygen as a converter material for the production of ultra-cold neutrons. In a first series of experiments the crystal preparation was examined. An optically semi-transparent solid alpha-oxygen crystal has been prepared. In a second series of experiments this crystal has been exposed to the cold neutron flux of the MEPHISTO beam line of the FRM II. Ultra-cold neutrons produced inside the oxygen crystal have been extracted and the count rates have been measured at different converter temperatures. The results of these measurements give a clear signal of the superthermal production mechanism due to antiferromagnetic lattice excitations in alpha-oxygen. The mean free loss length of UCN inside the crystal was determined to be approximately 30cm.

  3. Ultracold neutron accumulation in a superfluid-helium converter with magnetic multipole reflector

    E-Print Network [OSTI]

    O. Zimmer; R. Golub

    2015-03-04T23:59:59.000Z

    We analyze accumulation of ultracold neutrons (UCN) in a superfluid-helium converter vessel surrounded by a magnetic multipole reflector. We solved the spin-dependent rate equation, employing formulas valid for adiabatic spin transport of trapped UCN in mechanical equilibrium. Results for saturation UCN densities are obtained in dependence of order and strength of the multipolar field. The addition of magnetic storage to neutron optical potentials can increase the density and energy of the low field seeking UCN produced and serves to mitigate the effects of wall losses on the source performance. It also can provide a highly polarized sample of UCN without need to polarize the neutron beam incident on the converter. This work was performed in preparation of the UCN source project SuperSUN at the ILL.

  4. Solid oxygen as converter for the production of ultra-cold neutrons

    E-Print Network [OSTI]

    A. Frei; F. Bhle; R. Bozhanova; E. Gutsmiedl; T. Huber; J. Klenke; S. Paul; S. Wlokka

    2011-07-11T23:59:59.000Z

    We have investigated solid oxygen as a converter material for the production of ultra-cold neutrons. In a first series of experiments the crystal preparation was examined. An optically semi-transparent solid $\\alpha$-oxygen crystal has been prepared. In a second series of experiments such a crystal prepared indentically as in the first series of experiments has been exposed to the cold neutron flux of the MEPHISTO beam line of the FRM II. Ultra-cold neutrons produced inside the oxygen crystal have been extracted and the count rates have been measured at different converter temperatures. The results of these measurements give a clear signal of the superthermal UCN production mechanism in $\\alpha$-oxygen. The mean free loss length of UCN inside the crystal at a temperature of 5\\,K was determined to be in the order of $20\\,\\mathrm{cm}$.

  5. Solid state transport-based thermoelectric converter

    DOE Patents [OSTI]

    Hu, Zhiyu

    2010-04-13T23:59:59.000Z

    A solid state thermoelectric converter includes a thermally insulating separator layer, a semiconducting collector and an electron emitter. The electron emitter comprises a metal nanoparticle layer or plurality of metal nanocatalyst particles disposed on one side of said separator layer. A first electrically conductive lead is electrically coupled to the electron emitter. The collector layer is disposed on the other side of the separator layer, wherein the thickness of the separator layer is less than 1 .mu.m. A second conductive lead is electrically coupled to the collector layer.

  6. convert program | National Nuclear Security Administration

    National Nuclear Security Administration (NNSA)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOn AprilA Approved: 5-13-14Russian NuclearNational5/%2A en Office ofcontracting |convert

  7. Optical forces and optical torques on various materials arising from optical lattices in the Lorentz-Mie regime

    E-Print Network [OSTI]

    Jia, Lin

    By combining the Maxwell stress tensor with the finite-difference time-domain (FDTD) method, we calculate the optical force and optical torque on particles from optical lattices. We compare our method to the two-component ...

  8. Method and system for determining the torque required to launch a vehicle having a hybrid drive-train

    DOE Patents [OSTI]

    Hughes, Douglas A.

    2006-04-04T23:59:59.000Z

    A method and system are provided for determining the torque required to launch a vehicle having a hybrid drive-train that includes at least two independently operable prime movers. The method includes the steps of determining the value of at least one control parameter indicative of a vehicle operating condition, determining the torque required to launch the vehicle from the at least one determined control parameter, comparing the torque available from the prime movers to the torque required to launch the vehicle, and controlling operation of the prime movers to launch the vehicle in response to the comparing step. The system of the present invention includes a control unit configured to perform the steps of the method outlined above.

  9. VERIFICATION OF A FINITE ELEMENT MODEL OF AN UNMANNED AERIAL VEHICLE WING TORQUE BOX VIA EXPERIMENTAL MODAL TESTING

    E-Print Network [OSTI]

    Yaman, Yavuz

    code to extract the resonance frequencies and the corresponding mode-shapes of the wing torque was successfully flown. 1 Copyright 2012 by ASME Proceedings of the ASME 2012 11th Biennial Conference

  10. Power Maximization in Wave-Energy Converters Using Sampled -Data Extremum Seeking /

    E-Print Network [OSTI]

    Chen, Tianjia

    2013-01-01T23:59:59.000Z

    Power Maximization in Wave-Energy Converters Using Sampled-design optimization of wave energy converters con- sistingN. Sahinkaya. A review of wave energy converter technology.

  11. Calculation of rotordynamic unbalance response including torque and cross-coupled stiffness and damping effects

    E-Print Network [OSTI]

    Kleespies, Henry Sattoli

    1986-01-01T23:59:59.000Z

    code was developed using the transfer matrix method to investigate the effects of cross-coupled sti ffness, cross-coupled damping, and torque on synchronous response of rotating machinery. Several models showing the effects of cross.... Phase plot of rotor with ZX damping. Figure 3 1. Response plot for rotor with forward driving cross-coupled stiffness. Figure 32. Response plot with cross-coupled 53 55 57 sti ffness negating lateral damping. Figure 33. Response plot with cross...

  12. Integrated Solar Upper Stage (ISUS) thermionic converter string evaluation

    SciTech Connect (OSTI)

    Talbot, G.J.; Ramsey, W.D.; Chao, C.J.

    1998-07-01T23:59:59.000Z

    A serial string of eighth (8) thermionic converters were performance tested at New Mexico Engineering Research Institute (NMERI) by Frank Wyant et al1. The tests results from the second String Thermionic Assembly Research Testbed (START II) produced less than one half the expected power based on individual converter performance tests. Seven of the eight converters were returned to Lockheed Martin Information Systems-EOS for performance evaluation. Six of the seven produced nominal performance while the seventh converter showed a drastic reduction in performance due to a cesium leak to atmosphere. Several models were proposed to explain why the individual converter performance differed so markedly from the START II serial array. This paper discusses the models, evaluates model validity and compares the models with results from a tow converter serial test using of the returned START II converters.

  13. Dynamic Simulation of Shipping Package Subjected to Torque Load and Sequential Impacts

    SciTech Connect (OSTI)

    Wu, T

    2006-04-17T23:59:59.000Z

    A numerical technique has been developed to simulate the structural responses of radioactive material packaging components requiring closure-tightening torque to the scenarios of the hypothetical accident conditions (HAC) defined in the Code of Federal Regulations Title 10 part 71 (10CFR 71). A rigorous solution to this type of problem poses a considerable mathematical challenge. Conventional methods for evaluating the residue stresses due to the torque load are either inaccurate or not applicable to dynamic analyses. In addition, the HAC events occur sequentially and the cumulative damage to the package needs to be evaluated. Commonly, individual HAC events are analyzed separately and the cumulative damage is not addressed. As a result, strict compliance of the package with the requirements specified in 10CFR 71 is usually demonstrated by physical testing. The proposed technique utilizes the combination of kinematic constraints, rigid-body motions and structural deformations to overcome some of the difficulties encountered in modeling the effect of cumulative damage in numerical solutions. The analyses demonstrating use of this technique were performed to determine the cumulative damage of torque preload, a 30-foot drop, a 30-foot dynamic crush and a 40-inch free fall onto a mild steel pipe.

  14. Giant Planet Migration through the Action of Disk Torques and Planet Scattering

    E-Print Network [OSTI]

    Althea V. Moorhead; Fred C. Adams

    2005-05-11T23:59:59.000Z

    This paper presents a parametric study of giant planet migration through the combined action of disk torques and planet-planet scattering. The torques exerted on planets during Type II migration in circumstellar disks readily decrease the semi-major axes, whereas scattering between planets increases the orbital eccentricities. This paper presents a parametric exploration of the possible parameter space for this migration scenario using two (initial) planetary mass distributions and a range of values for the time scale of eccentricity damping (due to the disk). For each class of systems, many realizations of the simulations are performed in order to determine the distributions of the resulting orbital elements of the surviving planets; this paper presents the results of 8500 numerical experiments. Our goal is to study the physics of this particular migration mechanism and to test it against observations of extrasolar planets. The action of disk torques and planet-planet scattering results in a distribution of final orbital elements that fills the a-e plane, in rough agreement with the orbital elements of observed extrasolar planets. In addition to specifying the orbital elements, we characterize this migration mechanism by finding the percentages of ejected and accreted planets, the number of collisions, the dependence of outcomes on planetary masses, the time spent in 2:1 and 3:1 resonances, and the effects of the planetary IMF. We also determine the distribution of inclination angles of surviving planets and the distribution of ejection speeds for exiled planets.

  15. Lindblad resonance torques in relativistic discs: II. Computation of resonance strengths

    E-Print Network [OSTI]

    Christopher M. Hirata

    2011-03-01T23:59:59.000Z

    We present a fully relativistic computation of the torques due to Lindblad resonances from perturbers on circular, equatorial orbits on discs around Schwarzschild and Kerr black holes. The computation proceeds by establishing a relation between the Lindblad torques and the gravitational waveforms emitted by the perturber and a test particle in a slightly eccentric orbit at the radius of the Lindblad resonance. We show that our result reduces to the usual formula when taking the nonrelativistic limit. Discs around a black hole possess an m=1 inner Lindblad resonance with no Newtonian Keplerian analogue; however its strength is very weak even in the moderately relativistic regime (r/M ~ few tens), which is in part due to the partial cancellation of the two leading contributions to the resonant amplitude (the gravitoelectric octupole and gravitomagnetic quadrupole). For equatorial orbits around Kerr black holes, we find that the m=1 ILR strength is enhanced for retrograde spins and suppressed for prograde spins. We also find that the torque associated with the m>=2 inner Lindblad resonances is enhanced relative to the nonrelativistic case; the enhancement is a factor of 2 for the Schwarzschild hole even when the perturber is at a radius of 25M.

  16. Converting online algorithms to local computation algorithms

    E-Print Network [OSTI]

    Mansour, Yishay; Vardi, Shai; Xie, Ning

    2012-01-01T23:59:59.000Z

    We propose a general method for converting online algorithms to local computation algorithms by selecting a random permutation of the input, and simulating running the online algorithm. We bound the number of steps of the algorithm using a query tree, which models the dependencies between queries. We improve previous analyses of query trees on graphs of bounded degree, and extend the analysis to the cases where the degrees are distributed binomially, and to a special case of bipartite graphs. Using this method, we give a local computation algorithm for maximal matching in graphs of bounded degree, which runs in time and space O(log^3 n). We also show how to convert a large family of load balancing algorithms (related to balls and bins problems) to local computation algorithms. This gives several local load balancing algorithms which achieve the same approximation ratios as the online algorithms, but run in O(log n) time and space. Finally, we modify existing local computation algorithms for hypergraph 2-color...

  17. The capacitively coupled converter (C) for high power DC-DC conversion

    E-Print Network [OSTI]

    Khan, Shahriar

    1992-01-01T23:59:59.000Z

    A&M University. A combination of inherent capacitive commutation and gate turn-off switching devices (MCT, GTO, and ZTO) allows zero current switching, and reduces the switching losses to a minimum. This converter is capable of a wide ratio... to implement these switches and the power capability of the transistor can be increased manifold. If a high frequency capability is desired to reduce the sizes of the reactive elements, high power gate turn-off devices, such as the GTO, ZTO, or the MCT may...

  18. Catalogue of a Loss

    E-Print Network [OSTI]

    Berger, Larisa (Larisa A.)

    2012-01-01T23:59:59.000Z

    Catalogue of a Loss is a collection of sixty-two prose poems written within the past year and half. The work is printed on 4x6 cards. Each poem may be read individually from a single card or the poems can be read in ...

  19. Modular Power Converters for PV Applications

    SciTech Connect (OSTI)

    Ozpineci, Burak [ORNL; Tolbert, Leon M [ORNL

    2012-05-01T23:59:59.000Z

    This report describes technical opportunities to serve as parts of a technological roadmap for Shoals Technologies Group in power electronics for PV applications. There are many different power converter circuits that can be used for solar inverter applications. The present applications do not take advantage of the potential for using common modules. We envision that the development of a power electronics module could enable higher reliability by being durable and flexible. Modules would have fault current limiting features and detection circuits such that they can limit the current through the module from external faults and can identify and isolate internal faults such that the remaining modules can continue to operate with only minimal disturbance to the utility or customer. Development of a reliable, efficient, low-cost, power electronics module will be a key enabling technology for harnessing more power from solar panels and enable plug and play operation. Power electronics for computer power supplies, communication equipment, and transportation have all targeted reliability and modularity as key requirements and have begun concerted efforts to replace monolithic components with collections of common smart modules. This is happening on several levels including (1) device level with intelligent control, (2) functional module level, and (3) system module. This same effort is needed in power electronics for solar applications. Development of modular units will result in standard power electronic converters that will have a lower installed and operating cost for the overall system. These units will lead to increased adaptability and flexibility of solar inverters. Incorporating autonomous fault current limiting and reconfiguration capabilities into the modules and having redundant modules will lead to a durable converter that can withstand the rigors of solar power generation for more than 30 years. Our vision for the technology roadmap is that there is no need for detailed design of new power converters for each new application or installation. One set of modules and controllers can be pre-developed and the only design question would be how many modules need to be in series or parallel for the specific power requirement. Then, a designer can put the modules together and add the intelligent reconfigurable controller. The controller determines how many modules are connected, but it might also ask for user input for the specific application during setup. The modules include protection against faults and can reset it, if necessary. In case of a power device failure, the controller reconfigures itself to continue limited operation until repair which might be as simple as taking the faulty module out and inserting a new module. The result is cost savings in design, maintenance, repair, and a grid that is more reliable and available. This concept would be a perfect fit for the recently announced funding opportunity announcement (DE-FOA-0000653) on Plug and Play Photovoltaics.

  20. Design of series-parallel connected thermionic converter arrays

    SciTech Connect (OSTI)

    Mcvey, J.B.; Britt, E.J.; Fitzpatrick, G.O.; Dick, R.S.

    1981-01-01T23:59:59.000Z

    Applications of thermionic converters require that a large number of converters be connected together in a series-parallel array in order to provide a useful output voltage. Such an array also serves to insure a very high overall system reliability, despite possible failures of individual converters. This paper predicts the effects of a nonuniform distribution of input power on the performance of such an array. 9 refs.

  1. Method and apparatus for effecting light-off of a catalytic converter in a hybrid powertrain system

    DOE Patents [OSTI]

    Roos, Bryan Nathaniel; Spohn, Brian L

    2013-07-02T23:59:59.000Z

    A powertrain system includes a hybrid transmission and an internal combustion engine coupled to an exhaust aftertreatment device. A method for operating the powertrain system includes operating the hybrid transmission to generate tractive torque responsive to an operator torque request with the internal combustion engine in an engine-off state so long as the tractive torque is less than a threshold. The internal combustion engine is operated in an engine-on state at preferred operating conditions to effect light-off of the exhaust aftertreatment device and the hybrid transmission is coincidentally operated to generate tractive torque responsive to the operator torque request when the operator torque request exceeds the threshold. The internal combustion engine is then operated in the engine-on state to generate tractive torque responsive to the operator torque request.

  2. acid change converts: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Transmission, Distribution and Plants Websites Summary: converters can optimize the number of levels by using H bridges scaled in power of three. The shortcoming, the faulty...

  3. Sandia Energy - Sandia, NREL Release Wave Energy Converter Modeling...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Sandia, NREL Release Wave Energy Converter Modeling and Simulation Code: WEC-Sim Home Renewable Energy Energy Water Power Partnership News News & Events Computational Modeling &...

  4. DOE Announces Webinars on the Wave Energy Converter Prize, the...

    Broader source: Energy.gov (indexed) [DOE]

    24: Live Webinar on the Administration of the Wave Energy Converter Prize Funding Opportunity Announcement Webinar Sponsor: EERE Water Power Program The Energy Department will...

  5. Researchers hope better catalysts lead to better ways of converting...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Researchers hope better catalysts lead to better ways of converting biomass to fuel By Jared Sagoff * August 7, 2013 Tweet EmailPrint ARGONNE, Ill. - Scientists and entrepreneurs...

  6. ac to dc converters: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    to use solid state Inverters(DC to AC converters) to have a variable voltage, fixed or variable frequency power source available for industrial applications. With advancements...

  7. active npc converter: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Solid State Transformer Engineering Websites Summary: converters as distribution transformers 1. A power electronics-based solid state transformer (SST) providesAc-Ac Dual...

  8. alcohol angiotensin-converting-enzyme inhibitors: Topics by E...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    complications. There is no specific treatment for membranous nephropathy. Supportive care with the use of diuretics and angiotensin-converting enzyme inhibitors in combination...

  9. Integrated Solar Power Converters: Wafer-Level Sub-Module Integrated DC/DC Converter

    SciTech Connect (OSTI)

    None

    2012-02-09T23:59:59.000Z

    Solar ADEPT Project: CU-Boulder is developing advanced power conversion components that can be integrated into individual solar panels to improve energy yields. The solar energy that is absorbed and collected by a solar panel is converted into useable energy for the grid through an electronic component called an inverter. Many large, conventional solar energy systems use one, central inverter to convert energy. CU-Boulder is integrating smaller, microinverters into individual solar panels to improve the efficiency of energy collection. The Universitys microinverters rely on electrical components that direct energy at high speeds and ensure that minimal energy is lost during the conversion processimproving the overall efficiency of the power conversion process. CU-Boulder is designing its power conversion devices for use on any type of solar panel.

  10. Converter fed synchronous generator system for medium and large power plants

    SciTech Connect (OSTI)

    Ammann, C.; Reichert, K.; Joho, R.

    1986-06-01T23:59:59.000Z

    Converter fed synchronous generators have the following advantages: The turbine can operate at any speed, independent of the frequency of the power system, the part load efficiency may be improved if the speed can be adjusted. The generator is protected and isolated. The stability is improved. This scheme is applicable to hydro, steam and wind generation. The paper gives details on a converter fed 650 MW unit with steam turbine having a synchronous generator with two 3-phase windings at 30/sup 0/ to each other which directly feeds a 12-pulse HVDC link. The usual converter transformer, var-compensators and current harmonics filters on the generator side are eliminated. The study shows the advantages and disadvantages of the system. The system stability is considerably improved compared to the conventional design. As the steam turbine can be operated only with constant speed, the improvements in the efficiency of the thermal system are limited. A cost reduction can be achieved only with a higher turbine speed. Details are given on the total system losses and the total system costs in comparison to the conventional design.

  11. REDUCING MISMATCH LOSSES IN GRID-CONNECTED RESIDENTIAL BIPV ARRAYS USING ACTIVE POWER CONVERSION COMPONENTS

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    in plant energy production. The introduction of additional power converters in the plant layout intends/Simulink© environment for each topology using a 3 kWp rooftop-type plant. Simulation results show that a considerableREDUCING MISMATCH LOSSES IN GRID-CONNECTED RESIDENTIAL BIPV ARRAYS USING ACTIVE POWER CONVERSION

  12. TILAS: A Simple Analysis Tool for Estimating Power Losses in an IGBT-Diode Pair under

    E-Print Network [OSTI]

    Kimball, Jonathan W.

    measurements the load current of a converter phase leg and the gate switching waveform of the upper IGBT. The sizing and material of heat sinks, in addition to the choice of blowers, liquid cooling, heat pumps, etc case. In [3], an analytical calculation tool for power losses in both voltage-source and current

  13. Optimization of spin-torque switching using AC and DC pulses

    SciTech Connect (OSTI)

    Dunn, Tom [Department of Physics, University of Minnesota, Minneapolis, Minnesota 55455 (United States); Kamenev, Alex [Department of Physics, University of Minnesota, Minneapolis, Minnesota 55455 (United States); Fine Theoretical Physics Institute, University of Minnesota, Minneapolis, Minnesota 55455 (United States)

    2014-06-21T23:59:59.000Z

    We explore spin-torque induced magnetic reversal in magnetic tunnel junctions using combined AC and DC spin-current pulses. We calculate the optimal pulse times and current strengths for both AC and DC pulses as well as the optimal AC signal frequency, needed to minimize the Joule heat lost during the switching process. The results of this optimization are compared against numeric simulations. Finally, we show how this optimization leads to different dynamic regimes, where switching is optimized by either a purely AC or DC spin-current, or a combination AC/DC spin-current, depending on the anisotropy energies and the spin-current polarization.

  14. Parametric excitation in a magnetic tunnel junction-based spin torque oscillator

    SciTech Connect (OSTI)

    Drrenfeld, P.; Iacocca, E. [Department of Physics, University of Gothenburg, 412 96 Gothenburg (Sweden); kerman, J. [Department of Physics, University of Gothenburg, 412 96 Gothenburg (Sweden); Materials Physics, School of ICT, KTH-Royal Institute of Technology, Electrum 229, 164 40 Kista (Sweden); Muduli, P. K. [Department of Physics, University of Gothenburg, 412 96 Gothenburg (Sweden); Department of Physics, Indian Institute of Technology, Delhi, 110016 New Delhi (India)

    2014-02-03T23:59:59.000Z

    Using microwave current injection at room temperature, we demonstrate parametric excitation of a magnetic tunnel junction (MTJ)-based spin-torque oscillator (STO). Parametric excitation is observed for currents below the auto-oscillation threshold, when the microwave current frequency f{sub e} is twice the STO free-running frequency f{sub 0}. Above threshold, the MTJ becomes parametrically synchronized. In the synchronized state, the STO exhibits an integrated power up to 5 times higher and a linewidth reduction of two orders of magnitude, compared to free-running conditions. We also show that the parametric synchronization favors single mode oscillations in the case of multimode excitation.

  15. A 1 MEGAWATT POLYPHASE BOOST CONVERTER-MODULATOR FOR KLYSTRON PULSE APPLICATION

    SciTech Connect (OSTI)

    W.A. REASS; J.D. DOSS; R.F. GRIBBLE

    2001-06-01T23:59:59.000Z

    This paper describes electrical design criteria and first operational results a 140 kV, 1 MW average, 11 MW peak, zero-voltage-switching 20 kHz polyphase bridge, boost converter/modulator for klystron pulse application. The DC-DC converter derives the buss voltages from a standard 13.8 kV to 2300 Y substation cast-core transformer. Energy storage and filtering is provided by self-clearing metallized hazy polypropylene traction capacitors. Three ''H-Bridge'' Insulated Gate Bipolar Transistor (IGBT) switching networks are used to generate the polyphase 20 kHz transformer primary drive waveforms. The 20 kHz drive waveforms are chirped the appropriate duration to generate the desired klystron pulse width. PWM (pulse width modulation) of the individual 20 kHz pulses is utilized to provide regulated output waveforms with adaptive feedforward and feedback techniques. The boost transformer design utilizes amorphous nanocrystalline material that provides the required low core loss at design flux levels and switching frequencies. Resonant shunt-peaking is used on the transformer secondary to boost output voltage and resonate transformer leakage inductance. With the appropriate transformer leakage inductance and peaking capacitance, zero-voltage-switching of the IGBT's is attained, minimizing switching losses. A review of these design parameters and the first results of the performance characteristics will be presented.

  16. Design, status and first operations of the spallation neutron source polyphase resonant converter modulator system

    SciTech Connect (OSTI)

    Reass, W. A. (William A.); Apgar, S. E. (Sean E.); Baca, D. M. (David M.); Doss, James D.; Gonzales, J. (Jacqueline); Gribble, R. F. (Robert F.); Hardek, T. W. (Thomas W.); Lynch, M. T. (Michael T.); Rees, D. E. (Daniel E.); Tallerico, P. J. (Paul J.); Trujillo, P. B. (Pete B.); Anderson, D. E. (David E.); Heidenreich, D. A. (Dale A.); Hicks, J. D. (Jim D.); Leontiev, V. N.

    2003-01-01T23:59:59.000Z

    The Spallation Neutron Source (SNS) is a new 1.4 MW average power beam, 1 GeV accelerator being built at Oak Ridge National Laboratory. The accelerator requires 15 converter-modulator stations each providing between 9 and 11 MW pulses with up to a 1 .I MW average power. The converter-modulator can be described as a resonant 20 kHz polyphase boost inverter. Each converter modulator derives its buss voltage from a standard substation cast-core transformer. Each substation is followed by an SCR pre-regulator to accommodate voltage changes from no load to full load, in addition to providing a soft-start function. Energy storage is provided by self-clearing metallized hazy polypropylene traction capacitors. These capacitors do not fail short, but clear any internal anomaly. Three 'H-Bridge' IGBT transistor networks are used to generate the polyphase 20 kHz transformer primary drive waveforms. The 20 kHz drive waveforms are time-gated to generate the desired klystron pulse width. Pulse width modulation of the individual 20 lcHz pulses is utilized to provide regulated output waveforms with DSP based adaptive feedforward and feedback techniques. The boost transformer design utilizes nanocrystalline alloy that provides low core loss at design flux levels and switching frequencies. Capacitors are used on the transformer secondary networks to resonate the leakage inductance. The transformers are wound for a specific leakage inductance, not turns ratio. This design technique generates multiple secondary volts per turn as compared to the primary. With the appropriate tuning conditions, switching losses are minimized. The resonant topology has the added benefit of being deQed in a klystron fault condition, with little energy deposited in the arc. This obviates the need of crowbars or other related networks. A review of these design parameters, operational performance, production status, and OWL installation and performance to date will be presented.

  17. Optimizing Ballast Design of Wave Energy Converters Using Evolutionary Algorithms

    E-Print Network [OSTI]

    Tumer, Kagan

    Optimizing Ballast Design of Wave Energy Converters Using Evolutionary Algorithms Mitch Colby, 97331 kagan.tumer@oregonstate.edu ABSTRACT Wave energy converters promise to be a viable alternative the ballast geometry of a wave energy genera- tor using a two step process. First, we generate a function

  18. Drive System for Traction Applications Using 81-Level Converter

    E-Print Network [OSTI]

    Catholic University of Chile (Universidad Catlica de Chile)

    of frequency converter. Keywords: vehicle power electronics, vehicle motor drives. I. INTRODUCTION Power Electronics technologies contribute with important part in the development of electric vehicles. On the otherDrive System for Traction Applications Using 81-Level Converter Juan W. Dixon, Micah E. Ortzar

  19. Ability of Catalytic Converters to Reduce Air Pollution

    E-Print Network [OSTI]

    Nizkorodov, Sergey

    NOx - 1 Ability of Catalytic Converters to Reduce Air Pollution MEASUREMENT OF SELECTED AIR POLLUTANTS IN CAR EXHAUST Last updated: June 17, 2014 #12;NOx - 2 Ability of Catalytic Converters to Reduce Air Pollution MEASUREMENT OF SELECTED AIR POLLUTANTS IN CAR EXHAUST INTRODUCTION Automobile engines

  20. ORIGINAL PAPER Antioxidant and angiotensin-converting enzyme inhibitory

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    functions of these peptides derived from milk proteins are antioxidant and angiotensin-converting enzyme antioxidant activities of the peptides have been observed as chelation of transition metals and scavengingORIGINAL PAPER Antioxidant and angiotensin-converting enzyme inhibitory activity of yoghurt

  1. The frequency dependent impedance of an HVdc converter

    SciTech Connect (OSTI)

    Wood, A.R.; Arrillaga, J. [Univ. of Canterbury, Christchurch (New Zealand)] [Univ. of Canterbury, Christchurch (New Zealand)

    1995-07-01T23:59:59.000Z

    A linear and direct method of determining the frequency dependent impedance of a 12 pulse HVdc converter is presented. Terms are developed for both the dc and ac side impedances of the converter, including the effect of the firing angle control system, the commutation period, and the variability of the commutation period. The impedance predictions are verified by dynamic simulation.

  2. A study of Schwarz converters for nuclear powered spacecraft

    SciTech Connect (OSTI)

    Stuart, T.A. [Univ. of Toledo, OH (United States); Schwarze, G.E. [Lewis Research Center, Cleveland, OH (United States)

    1994-09-01T23:59:59.000Z

    High power space systems which use low dc voltage, high current sources such as thermoelectric generators, will most likely require high voltage conversion for transmission purposes. This study considers the use of the Schwarz resonant converter for use as the basic building block to accomplish this low-to-high voltage conversion for either a dc or an ac spacecraft bus. The Schwarz converter has the important assets of both inherent fault tolerance and resonant operation and parallel operation in modular form is possible. A regulated dc spacecraft bus requires only a single stage converter while a constant frequency ac bus requires a cascaded Schwarz converter configuration. If the power system requires constant output power from the dc generator, then a second converter is required to route unneeded power to a ballast load.

  3. A computer program for HVDC converter station RF noise calculations

    SciTech Connect (OSTI)

    Kasten, D.G.; Caldecott, R.; Sebo, S.A. (Ohio State Univ., Columbus, OH (United States). Dept. of Electrical Engineering); Liu, Y. (Virginia Polytechnic Inst. State Univ., Blacksburg, VA (United States). Bradley Dept. of Electrical Engineering)

    1994-04-01T23:59:59.000Z

    HVDC converter station operations generate radio frequency (RF) electromagnetic (EM) noise which could interfere with adjacent communication and computer equipment, and carrier system operations. A generic Radio Frequency Computer Analysis Program (RAFCAP) for calculating the EM noise generated by valve ignition of a converter station has been developed as part of a larger project. The program calculates RF voltages, currents, complex power, ground level electric field strength and magnetic flux density in and around an HVDC converter station. The program requires the converter station network to be represented by frequency dependent impedance functions. Comparisons of calculated and measured values are given for an actual HVDC station to illustrate the validity of the program. RAFCAP is designed to be used by engineers for the purpose of calculating the RF noise produced by the igniting of HVDC converter valves.

  4. DYNAMIC ANALYSIS OF THE BULK TRITIUM SHIPPING PACKAGE SUBJECTED TO CLOSURE TORQUES AND SEQUENTIAL IMPACTS

    SciTech Connect (OSTI)

    Wu, T; Paul Blanton, P; Kurt Eberl, K

    2007-07-09T23:59:59.000Z

    This paper presents a finite-element technique to simulate the structural responses and to evaluate the cumulative damage of a radioactive material packaging requiring bolt closure-tightening torque and subjected to the scenarios of the Hypothetical Accident Conditions (HAC) defined in the Code of Federal Regulations Title 10 part 71 (10CFR71). Existing finite-element methods for modeling closure stresses from bolt pre-load are not readily adaptable to dynamic analyses. The HAC events are required to occur sequentially per 10CFR71 and thus the evaluation of the cumulative damage is desirable. Generally, each HAC event is analyzed separately and the cumulative damage is partially addressed by superposition. This results in relying on additional physical testing to comply with 10CFR71 requirements for assessment of cumulative damage. The proposed technique utilizes the combination of kinematic constraints, rigid-body motions and structural deformations to overcome some of the difficulties encountered in modeling the effect of cumulative damage. This methodology provides improved numerical solutions in compliance with the 10CFR71 requirements for sequential HAC tests. Analyses were performed for the Bulk Tritium Shipping Package (BTSP) designed by Savannah River National Laboratory to demonstrate the applications of the technique. The methodology proposed simulates the closure bolt torque preload followed by the sequential HAC events, the 30-foot drop and the 30-foot dynamic crush. The analytical results will be compared to the package test data.

  5. Midlatitude Ozone: Loss and Trends

    E-Print Network [OSTI]

    Toohey, Darin W.

    1 Lecture 17 Midlatitude Ozone: Loss and Trends ATOC/CHEM 5151 #12;2 Importance of midlatitude ozone Covers most of the world's populated areas Provides protection from UV #12;3 Ozone loss picture, c. 1988 #12;4 Lower vs. Upper stratosphere #12;5 Ozone loss, post 1988 Discovery of ozone hole

  6. Wind turbines convert the kinetic energy in moving air into rotational energy, which in turn is converted

    E-Print Network [OSTI]

    Massachusetts at Amherst, University of

    Wind turbines convert the kinetic energy in moving air into rotational energy, which in turn is converted to electricity. Since wind speeds vary from month to month and second to second, the amount of electricity wind can make varies constantly. Sometimes a wind turbine will make no power at all

  7. 3-Port Single-Stage PV & Battery Converter Improves Efficiency and Cost in Combined PV/Battery Systems

    SciTech Connect (OSTI)

    Bundschuh, Paul [Ideal Power

    2013-03-23T23:59:59.000Z

    Due to impressive cost reductions in recent years, photovoltaic (PV) generation is now able to produce electricity at highly competitive prices, but PVs inherent intermittency reduces the potential value of this energy. The integration of battery storage with PV will be transformational by increasing the value of solar. Utility scale systems will benefit by firming intermittency including PV ramp smoothing, grid support and load shifting, allowing PV to compete directly with conventional generation. For distributed grid-tied PV adding storage will reduce peak demand utility charges, as well as providing backup power during power grid failures. The largest long term impact of combined PV and battery systems may be for delivering reliable off-grid power to the billions of individuals globally without access to conventional power grids, or for billions more that suffer from daily power outages. PV module costs no longer dominate installed PV system costs. Balance-of-System (BOS) costs including the PV inverter and installation now contribute the majority of installed system costs. Battery costs are also dropping faster than installation and battery power converter systems. In each of these separate systems power converters have become a bottleneck for efficiency, cost and reliability. These bottlenecks are compounded in hybrid power conversion systems that combine separate PV and battery converters. Hybrid power conversion systems have required multiple power converters hardware units and multiple power conversion steps adding to efficiency losses, product and installation costs, and reliability issues. Ideal Power Converters has developed and patented a completely new theory of operation for electronic power converters using its indirect EnergyPacket Switching topology. It has established successful power converter products for both PV and battery systems, and its 3-Port Hybrid Converter is the first product to exploit the topologys capability for the industrys first single-stage multi-port hybrid power converter. This unique low cost approach eliminates the hybrid power conversion bottlenecks when integrating batteries into PV systems. As result this product will significantly accelerate market adoption of these systems.

  8. Magnet Technology for Power Converters: Nanocomposite Magnet Technology for High Frequency MW-Scale Power Converters

    SciTech Connect (OSTI)

    None

    2012-02-27T23:59:59.000Z

    Solar ADEPT Project: CMU is developing a new nanoscale magnetic material that will reduce the size, weight, and cost of utility-scale PV solar power conversion systems that connect directly to the grid. Power converters are required to turn the energy that solar power systems create into useable energy for the grid. The power conversion systems made with CMUs nanoscale magnetic material have the potential to be 150 times lighter and significantly smaller than conventional power conversion systems that produce similar amounts of power.

  9. Exchanging Ohmic Losses in Metamaterial Absorbers with Useful Optical Absorption for Photovoltaics

    E-Print Network [OSTI]

    Vora, Ankit; Pala, Nezih; Kulkarni, Anand; Pearce, Joshua M; Gney, Durdu

    2014-01-01T23:59:59.000Z

    Using metamaterial absorbers, we have shown that metallic layers in the absorbers do not necessarily constitute undesired resistive heating problem for photovoltaics. Tailoring the geometric skin depth of metals and employing the natural bulk absorbance characteristics of the semiconductors in those absorbers can enable the exchange of undesired resistive losses with the useful optical absorbance in the active semiconductors. Thus, Ohmic loss dominated metamaterial absorbers can be converted into photovoltaic near-perfect absorbers with the advantage of harvesting the full potential of light management offered by the metamaterial absorbers. Based on experimental permittivity data for indium gallium nitride, we have shown that between 75%-95% absorbance can be achieved in the semiconductor layers of the converted metamaterial absorbers. Besides other metamaterial and plasmonic devices, our results may also apply to photodectors and other metal or semiconductor based optical devices where resistive losses and p...

  10. Method for reducing energy losses in laser crystals

    DOE Patents [OSTI]

    Atherton, L.J.; DeYoreo, J.J.; Roberts, D.H.

    1992-03-24T23:59:59.000Z

    A process for reducing energy losses in crystals is disclosed which comprises: a. heating a crystal to a temperature sufficiently high as to cause dissolution of microscopic inclusions into the crystal, thereby converting said inclusions into point-defects, and b. maintaining said crystal at a given temperature for a period of time sufficient to cause said point-defects to diffuse out of said crystal. Also disclosed are crystals treated by the process, and lasers utilizing the crystals as a source of light. 12 figs.

  11. Evaluation of friction loss in flexible and galvanized duct

    E-Print Network [OSTI]

    Zimmermann, Carlos Michael Alberto

    1985-01-01T23:59:59.000Z

    for Friction Loss in Straight Runs of Duct (a'Ipha=0. 10). 21 Ill Static Pressure Data Converted to Equivalent Lengths. 23 IV Duncan's Multiple Range Test of Variability for Equivalent Lengths of 90 Degree Elbows (al pha=0. IO). 26 V Student t Test... in the system was controlled by a discharge damper and metered with an orifice meter. The static pressure data was collected by the use of a pizometer ring located at the exhaust portion of the test apparatus where the flexible duct was connected...

  12. Motor torque compensation of an induction electric motor by adjusting a slip command during periods of supposed change in motor temperature

    SciTech Connect (OSTI)

    Kelledes, William L. (Brighton, MI); St. John, Don K. (Livonia, MI)

    1992-01-01T23:59:59.000Z

    The present invention maintains constant torque in an inverter driven AC induction motor during variations in rotor temperature. It is known that the torque output of a given AC induction motor is dependent upon rotor temperature. At rotor temperatures higher than the nominal operating condition the rotor impedance increases, reducing the rotor current and motor torque. In a similar fashion, the rotor impedance is reduced resulting in increased rotor current and motor torque when the rotor temperature is lower than the nominal operating condition. The present invention monitors the bus current from the DC supply to the inverter and adjusts the slip frequency of the inverter drive to maintain a constant motor torque. This adjustment is based upon whether predetermined conditions implying increased rotor temperature or decreased rotor temperature exist for longer that a predetermined interval of time.

  13. Ion trapping in the emitter sheath in thermionic converters

    SciTech Connect (OSTI)

    Lundgren, L.

    1985-12-01T23:59:59.000Z

    The effect of ion trapping in the emitter sheath in ignited thermionic converters is studied. The ion trapping prevents the emitter-sheath barrier from being higher than approximately 0.1 eV, when the current decreases in the converter. This gives a condition for the constriction of the arc. I-V curves are calculated for an ignited thermionic converter with a hydrodynamic plasma theory that takes into account the effect of Coulomb scattering and volume recombination, but assumes that the electron temperature is constant in the plasma.

  14. Design and operation of a thermionic converter in air

    SciTech Connect (OSTI)

    Horner, M.H.; Begg, L.L.; Smith, J.N. Jr. [General Atomics, San Diego, CA (United States); Geller, C.B.; Kallnowski, J.E. [Westinghouse Electric Corp., West Mifflin, PA (United States). Bettis Atomic Power Lab.

    1995-01-01T23:59:59.000Z

    An electrically heated thermionic converter has been designed, built and successfully tested in air. Several unique features were incorporated in this converter: an integral cesium reservoir, innovative ceramic-to-metal seals, a heat rejection system coupling the collector to a low temperature heat sink and an innovative cylindrical heater filament. The converter was operated for extended periods of time with the emitter at about 1900 K. the collector at about 700 K, and a power density of over 2 w(e)/sq. cm. Input power transients were run between 50% and 100% thermal power, at up to 1% per second, without instabilities in performance.

  15. Prediction of core saturation instability at an HVDC converter

    SciTech Connect (OSTI)

    Burton, R.S. [Teshmont Consultants, Inc., Winnipeg, Manitoba (Canada)] [Teshmont Consultants, Inc., Winnipeg, Manitoba (Canada); Fuchshuber, C.F. [Alberta Power Ltd., Edmonton, Alberta (Canada)] [Alberta Power Ltd., Edmonton, Alberta (Canada); Woodford, D.A. [Manitoba HVDC Research Centre, Winnipeg, Manitoba (Canada)] [Manitoba HVDC Research Centre, Winnipeg, Manitoba (Canada); Gole, A.M. [Univ. of Manitoba, Winnipeg, Manitoba (Canada)] [Univ. of Manitoba, Winnipeg, Manitoba (Canada)

    1996-10-01T23:59:59.000Z

    Core saturation instability has occurred on several HVDC schemes resulting from interactions between second harmonic and dc quantities (voltages and currents) on the ac side of the converter and fundamental frequency quantities on the dc side of the converter. The instability can be reinforced by unbalanced saturation of the converter transformers. The paper presents an analytical method which can be used to quickly screen ac and dc system operating conditions to predict where core saturation instability is likely to occur. Analytical results have been confirmed using the digital transients simulation program PSCAD/EMTDC.

  16. Abstract--The paper focuses on design and control of a new anthropomorphic robot arm enabling the torque measurement

    E-Print Network [OSTI]

    Tachi, Susumu

    Abstract--The paper focuses on design and control of a new anthropomorphic robot arm enabling provides active compliance of corresponding robot arm joint. Thus, the whole structure of the manipulator the design procedure of 4-DOF robot arm and optical torque sensors. The experimental results of variable

  17. The effect of an external torque on low to high confinement transitions D. E. Newman and B. A. Carreras

    E-Print Network [OSTI]

    Newman, David

    , an external torque term is added to the poioidai momentum balance equation. It is found, analyti- cally. These equations exhibit a bifurcation between an L-mode fixed point and an H-mode fixed point with variation changes in a manner analogous to the addition of an external magnetic field to a ferromagnetic materiaL

  18. Journal of Energy and Power Engineering 5 (2011) 554-561 Load Torque Compensator for Model Predictive Direct

    E-Print Network [OSTI]

    Schaltz, Erik

    Predictive Direct Current Control in High Power PMSM Drive Systems M. Preindl1, 2 and E. Schaltz2 1. Power Magnet Synchronous Machine (PMSM), it contains an inner current i.e. torque control loop and an outer for Model Predictive Direct Current Control in High Power PMSM Drive Systems 555 Fig. 1 Block diagram

  19. Low torque hydrodynamic lip geometry for bi-directional rotation seals

    DOE Patents [OSTI]

    Dietle, Lannie L. (Houston, TX); Schroeder, John E. (Richmond, TX)

    2011-11-15T23:59:59.000Z

    A hydrodynamically lubricating geometry for the generally circular dynamic sealing lip of rotary seals that are employed to partition a lubricant from an environment. The dynamic sealing lip is provided for establishing compressed sealing engagement with a relatively rotatable surface, and for wedging a film of lubricating fluid into the interface between the dynamic sealing lip and the relatively rotatable surface in response to relative rotation that may occur in the clockwise or the counter-clockwise direction. A wave form incorporating an elongated dimple provides the gradual convergence, efficient impingement angle, and gradual interfacial contact pressure rise that are conducive to efficient hydrodynamic wedging. Skewed elevated contact pressure zones produced by compression edge effects provide for controlled lubricant movement within the dynamic sealing interface between the seal and the relatively rotatable surface, producing enhanced lubrication and low running torque.

  20. Low torque hydrodynamic lip geometry for bi-directional rotation seals

    DOE Patents [OSTI]

    Dietle, Lannie L. (Houston, TX); Schroeder, John E. (Richmond, TX)

    2009-07-21T23:59:59.000Z

    A hydrodynamically lubricating geometry for the generally circular dynamic sealing lip of rotary seals that are employed to partition a lubricant from an environment. The dynamic sealing lip is provided for establishing compressed sealing engagement with a relatively rotatable surface, and for wedging a film of lubricating fluid into the interface between the dynamic sealing lip and the relatively rotatable surface in response to relative rotation that may occur in the clockwise or the counter-clockwise direction. A wave form incorporating an elongated dimple provides the gradual convergence, efficient impingement angle, and gradual interfacial contact pressure rise that are conducive to efficient hydrodynamic wedging. Skewed elevated contact pressure zones produced by compression edge effects provide for controlled lubricant movement within the dynamic sealing interface between the seal and the relatively rotatable surface, producing enhanced lubrication and low running torque.

  1. Fast deterministic switching in orthogonal spin torque devices via the control of the relative spin polarizations

    SciTech Connect (OSTI)

    Park, Junbo; Buhrman, R. A. [Cornell University, Ithaca, New York 14853 (United States)] [Cornell University, Ithaca, New York 14853 (United States); Ralph, D. C. [Cornell University, Ithaca, New York 14853 (United States) [Cornell University, Ithaca, New York 14853 (United States); Kavli Institute at Cornell, Ithaca, New York 14853 (United States)

    2013-12-16T23:59:59.000Z

    We model 100 ps pulse switching dynamics of orthogonal spin transfer (OST) devices that employ an out-of-plane polarizer and an in-plane polarizer. Simulation results indicate that increasing the spin polarization ratio, C{sub P}?=?P{sub IPP}/P{sub OPP}, results in deterministic switching of the free layer without over-rotation (360 rotation). By using spin torque asymmetry to realize an enhanced effective P{sub IPP}, we experimentally demonstrate this behavior in OST devices in parallel to anti-parallel switching. Modeling predicts that decreasing the effective demagnetization field can substantially reduce the minimum C{sub P} required to attain deterministic switching, while retaining low critical switching current, I{sub p}???500??A.

  2. Spin alignments within the cosmic web: a theory of constrained tidal torques near filaments

    E-Print Network [OSTI]

    Codis, Sandrine; Pogosyan, Dmitry

    2015-01-01T23:59:59.000Z

    The geometry of the cosmic web drives in part the spin acquisition of galaxies. This can be explained in a Lagrangian framework, by identifying the specific long-wavelength correlations within the primordial Gaussian random field which are relevant to spin acquisition. Tidal Torque Theory is revisited in the context of such anisotropic environments, biased by the presence of a filament within a wall. The point process of filament-type saddles represents it most efficiently. The constrained misalignment between the tidal and the inertia tensors in the vicinity of filament-type saddles simply explains the distribution of spin directions. This misalignment implies in particular an azimuthal orientation for the spins of more massive galaxies and a spin alignment with the filament for less massive galaxies. This prediction is found to be in qualitative agreement with measurements in Gaussian random fields and N-body simulations. It relates the transition mass to the geometry of the saddle, and accordingly predicts...

  3. Frequency stabilization of spin-torque-driven oscillations by coupling with a magnetic nonlinear resonator

    SciTech Connect (OSTI)

    Kudo, Kiwamu, E-mail: kiwamu.kudo@toshiba.co.jp; Suto, Hirofumi; Nagasawa, Tazumi; Mizushima, Koichi; Sato, Rie [Corporate Research and Development Center, Toshiba Corporation, Kawasaki 2128582 (Japan)

    2014-10-28T23:59:59.000Z

    The fundamental function of any oscillator is to produce a waveform with a stable frequency. Here, we show a method of frequency stabilization for spin-torque nano-oscillators (STNOs) that relies on coupling with an adjacent nanomagnet through the magnetic dipoledipole interaction. It is numerically demonstrated that highly stable oscillations occur as a result of mutual feedback between an STNO and a nanomagnet. The nanomagnet acts as a nonlinear resonator for the STNO. This method is based on the nonlinear behavior of the resonator and can be considered as a magnetic analogue of an optimization scheme in nanoelectromechanical systems. The oscillation frequency is most stabilized when the nanomagnet is driven at a special feedback point at which the feedback noise between the STNO and resonator is completely eliminated.

  4. Idaho Application for Permit to Convert a Geothermal Injection...

    Open Energy Info (EERE)

    navigation, search OpenEI Reference LibraryAdd to library Form: Idaho Application for Permit to Convert a Geothermal Injection Well - Form 4003-3 Form Type ApplicationNotice Form...

  5. Multilevel Converter Topologies for Utility Scale Solar Photovoltaic Power Systems

    E-Print Network [OSTI]

    Essakiappan, Somasundaram

    2014-04-30T23:59:59.000Z

    sources like photovoltaics (PV) to the utility grid, some of which are multilevel topologies. Multilevel topologies allow for use of lower voltage semiconductor devices than two-level converters. They also produce lower distortion output voltage waveforms...

  6. Oversampled pipline A/D converters with mismatch shaping

    E-Print Network [OSTI]

    Shabra, Ayman U. (Ayman Umar)

    2001-01-01T23:59:59.000Z

    This thesis introduces a technique to improve the linearity of pipeline analog to digital converters (ADC). Through a combination of oversampling and mismatch shaping, the distortion introduced by component mismatch is ...

  7. Protocols for the Equitable Assessment of Marine Energy Converters

    E-Print Network [OSTI]

    Ingram, David; Smith, George; Bittencourt-Ferreira, Claudio; Smith, Helen

    This book contains the suite of protocols for the equitable evaluation of marine energy converters (based on either tidal or wave energy) produced by the EquiMar consortium led by the University of Edinburgh. These protocols ...

  8. Monolithic series-connected gallium arsenide converter development

    SciTech Connect (OSTI)

    Spitzer, M.B.; McClelland, R.W.; Dingle, B.D.; Dingle, J.E.; Hill, D.S. (Kopin Corp., Taunton, MA (United States)); Rose, B.H. (Sandia National Labs., Albuquerque, NM (United States))

    1991-01-01T23:59:59.000Z

    We report the development of monolithic GaAs photovoltaic devices intended to convert light generated by a laser or other bright source to electricity. The converters described here can provide higher operating voltage than is possible using a single-junction converter, owing to use of a monolithic circuit that forms a planar series-connected string of single-junction sub-cells. This planar monolithic circuit is arranged to deliver the desired voltage and current during operation at the maximum power point. The paper describes two-, six-, and twelve-junction converters intended for illumination by a laser diode with a wavelength of 0.8 {mu}m. Design and characterization data are presented for optical power in the range of 100 mW to 1 W. The best conversion efficiency exceeds 50%. 9 refs., 4 figs., 2 tabs.

  9. Automated Synthesis Tool for Design Optimization of Power Electronic Converters

    E-Print Network [OSTI]

    Mirjafari, Mehran

    2013-01-09T23:59:59.000Z

    Designers of power electronic converters usually face the challenge of having multiple performance indices that must be simultaneously optimized, such as maximizing efficiency while minimizing mass or maximizing reliability while minimizing cost...

  10. Sandia National Laboratories: resonant wave-energy converter...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    resonant wave-energy converter devices Inter-Agency Agreement Signed between DOE's Wind and Water Power Program and Carderock On December 3, 2014, in Energy, News, News & Events,...

  11. Photo of the Week: Converting Solar Energy into Fuel | Department...

    Broader source: Energy.gov (indexed) [DOE]

    toured the facilities that produce wind power generators and converters, in addition to PV solar inverters. In this photo he looks at a Stator 2MW Wind Turbine Generator. | Photo...

  12. Multiport Converter Topologies for Distributed Energy System Applications

    E-Print Network [OSTI]

    Hawke, Joshua

    2014-07-28T23:59:59.000Z

    fuel cell hybrid energy storage (MFC+HES) converter. First, low-voltage and medium-voltage PSC architectures are shown to decouple series-connected source currents and enable independent control. Multidimensional modeling and analysis is then discussed...

  13. A global maximum power point tracking DC-DC converter

    E-Print Network [OSTI]

    Duncan, Joseph, 1981-

    2005-01-01T23:59:59.000Z

    This thesis describes the design, and validation of a maximum power point tracking DC-DC converter capable of following the true global maximum power point in the presence of other local maximum. It does this without the ...

  14. MATHEMATICAL ANALYSIS OF A WAVE ENERGY CONVERTER ARNAUD ROUGIREL

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    for buoy-type ocean wave energy converter. The simplest model for this scheme is a non autonomous piecewise): see [OOS10]. Basically, a WEC is a floating body with a power takeoff system. It uses the vertical

  15. Method for converting uranium oxides to uranium metal

    DOE Patents [OSTI]

    Duerksen, Walter K. (Norris, TN)

    1988-01-01T23:59:59.000Z

    A process is described for converting scrap and waste uranium oxide to uranium metal. The uranium oxide is sequentially reduced with a suitable reducing agent to a mixture of uranium metal and oxide products. The uranium metal is then converted to uranium hydride and the uranium hydride-containing mixture is then cooled to a temperature less than -100.degree. C. in an inert liquid which renders the uranium hydride ferromagnetic. The uranium hydride is then magnetically separated from the cooled mixture. The separated uranium hydride is readily converted to uranium metal by heating in an inert atmosphere. This process is environmentally acceptable and eliminates the use of hydrogen fluoride as well as the explosive conditions encountered in the previously employed bomb-reduction processes utilized for converting uranium oxides to uranium metal.

  16. A Dual Supply Buck Converter with Improved Light Load Efficiency

    E-Print Network [OSTI]

    Chen, Hui

    2013-05-02T23:59:59.000Z

    Power consumption is the primary concern in battery-operated portable applications. Buck converters have gained popularity in powering portable devices due to their compact size, good current delivery capability and high efficiency. However...

  17. Development, evaluation, and design applications of an AMTEC converter model

    E-Print Network [OSTI]

    Spence, Cliff Alan

    2002-01-01T23:59:59.000Z

    An AMTEC converter model was developed and its effectiveness as a design tool was evaluated. To develop the model, requirements of the model were defined, modeling equations were selected, and a methodology for model development was established...

  18. Vehicle Technologies Office Merit Review 2014: WBG Converters and Chargers

    Broader source: Energy.gov [DOE]

    Presentation given by Oak Ridge National Laboratory at 2014 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office Annual Merit Review and Peer Evaluation Meeting about WBG converters...

  19. Non-synchronous control of self-oscillating resonant converters

    DOE Patents [OSTI]

    Glaser, John Stanley (Niskayuna, NY); Zane, Regan Andrew (Scotia, NY)

    2002-01-01T23:59:59.000Z

    A self-oscillating switching power converter has a controllable reactance including an active device connected to a reactive element, wherein the effective reactance of the reactance and the active device is controlled such that the control waveform for the active device is binary digital and is not synchronized with the switching converter output frequency. The active device is turned completely on and off at a frequency that is substantially greater than the maximum frequency imposed on the output terminals of the active device. The effect is to vary the average resistance across the active device output terminals, and thus the effective output reactance, thereby providing converter output control, while maintaining the response speed of the converter.

  20. Randomized modulation of power converters via Markov chains

    E-Print Network [OSTI]

    Stankovic, Aleksandar M.

    Randomized modulation of switching in power converters holds promise for reducing filtering requirements and reducing acoustic noise in motor drive applications. This paper is devoted to issues in analysis and synthesis ...

  1. JOURNAL DE PHYSIQUE Col2oque C 1, supplkment au no2-3, Tome 32, Fkvrier-Mars 1971,page C 1 -57 MAGNETIC TORQUE STUDY OF MnCr204 AT LOW TEMPERATURES

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    were glued. Above Ts (high temperature phase : HTP) we obtained ordinary torque curves without hyste. RESULTSFOR HTP (ABOVE18OK). - An exam- ple of torque curves is shown in figure 1. Obtained FIG.I. -The torque splitting. If we assume that, even in HTP, transverse components of magnetic moment of individual ions

  2. A New Methodology for Frequency Domain Analysis of Wave Energy Converters with Periodically Varying Physical Parameters

    E-Print Network [OSTI]

    Victoria, University of

    A New Methodology for Frequency Domain Analysis of Wave Energy Converters with Periodically Varying Methodology for Frequency Domain Analysis of Wave Energy Converters with Periodically Varying Physical of Mechanical Engineering) ABSTRACT Within a wave energy converter's operational bandwidth, device operation

  3. Bi-directional Current-fed Medium Frequency Transformer Isolated AC-DC Converter

    E-Print Network [OSTI]

    Essakiappan, Somasundaram

    2011-08-08T23:59:59.000Z

    The use of high power converters has increased tremendously. Increased demand for transportation, housing and industrial needs means that more number of power converters interact with the utility power grid. These converters are non...

  4. Analysis and design of matrix converters for adjustable speed drives and distributed power sources

    E-Print Network [OSTI]

    Cha, Han Ju

    2004-11-15T23:59:59.000Z

    Recently, matrix converter has received considerable interest as a viable alternative to the conventional back-to-back PWM (Pulse Width Modulation) converter in the ac/ac conversion. This direct ac/ac converter provides some attractive...

  5. Formation of double-valued sheaths in thermionic converters

    SciTech Connect (OSTI)

    Lundgren, L.

    1983-08-01T23:59:59.000Z

    A theory for the sheath in an ignited thermionic converter is presented. The theory includes the effect of the velocity spread of the particles but the charge-particle collisions are neglected. Conditions for the appearance of a virtual emitter are given. The theory is compared with a beam approximation theory and a hydrodynamic theory. All three theories give almost the same condition for the appearance of a virtual emitter in an ignited thermionic converter.

  6. Bi-directional power control system for voltage converter

    DOE Patents [OSTI]

    Garrigan, N.R.; King, R.D.; Schwartz, J.E.

    1999-05-11T23:59:59.000Z

    A control system for a voltage converter includes: a power comparator for comparing a power signal on input terminals of the converter with a commanded power signal and producing a power comparison signal; a power regulator for transforming the power comparison signal to a commanded current signal; a current comparator for comparing the commanded current signal with a measured current signal on output terminals of the converter and producing a current comparison signal; a current regulator for transforming the current comparison signal to a pulse width modulator (PWM) duty cycle command signal; and a PWM for using the PWM duty cycle command signal to control electrical switches of the converter. The control system may further include: a command multiplier for converting a voltage signal across the output terminals of the converter to a gain signal having a value between zero (0) and unity (1), and a power multiplier for multiplying the commanded power signal by the gain signal to provide a limited commanded power signal, wherein power comparator compares the limited commanded power signal with the power signal on the input terminals. 10 figs.

  7. Bi-directional power control system for voltage converter

    DOE Patents [OSTI]

    Garrigan, Neil Richard (Niskayuna, NY); King, Robert Dean (Schenectady, NY); Schwartz, James Edward (Slingerlands, NY)

    1999-01-01T23:59:59.000Z

    A control system for a voltage converter includes: a power comparator for comparing a power signal on input terminals of the converter with a commanded power signal and producing a power comparison signal; a power regulator for transforming the power comparison signal to a commanded current signal; a current comparator for comparing the commanded current signal with a measured current signal on output terminals of the converter and producing a current comparison signal; a current regulator for transforming the current comparison signal to a pulse width modulator (PWM) duty cycle command signal; and a PWM for using the PWM duty cycle command signal to control electrical switches of the converter. The control system may further include: a command multiplier for converting a voltage signal across the output terminals of the converter to a gain signal having a value between zero (0) and unity (1), and a power multiplier for multiplying the commanded power signal by the gain signal to provide a limited commanded power signal, wherein power comparator compares the limited commanded power signal with the power signal on the input terminals.

  8. Tax aspects of casualty losses

    E-Print Network [OSTI]

    Lehmann, August Herman

    1960-01-01T23:59:59.000Z

    sudden, unex- 1 pected or unusual nature. The word also signifies an accident, a mishap, or some sudden invasion by a hostile agency. It excludes the progressive deterioration of property through a steadily operating cause, and the loss of an article.... F. T, R. 432, rulings and Court decisions indicate that there may be a tendency to dis- regard suddenness as a requirement for a casualty loss deduction. The casualty loss deduction is allowed only for the loss of pro- 3 perty and the property...

  9. angiotensin-i converting enzyme: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Websites Summary: - Resonant converters and related systems, such as piezoelectric transformers, may require a high of resonant converters: a series-resonant parallel-...

  10. ac-dc-ac z-source converter: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Websites Summary: - Resonant converters and related systems, such as piezoelectric transformers, may require a high of resonant converters: a series-resonant parallel-...

  11. DOE-TSPP-8-2013, Converting DOE Technical Standards to Voluntary...

    Energy Savers [EERE]

    8-2013, Converting DOE Technical Standards to Voluntary Consensus Standards DOE-TSPP-8-2013, Converting DOE Technical Standards to Voluntary Consensus Standards Technical Standards...

  12. The polyphase resonant converter modulator for pulse power and plasma applications

    SciTech Connect (OSTI)

    Reass, W. A. (William A.); Baca, D. M. (David M.); Doss, James D.; Gribble, R. (Robert F.); North, W. R.

    2002-01-01T23:59:59.000Z

    This paper describes a new technique to generate high voltage pulses (100 kV and up) with high peak power (10 MW and up) and high average power (1 MW and up) from a low voltage input source (e.g. +/- 1.2 kV). This technology is presently being used to provide cathode pulse modulation for the Spallation Neutron Source (SNS) accelerator klystron RF amplifiers, which operate to 140 kV 11 MW peak power and 1.1 MW average power. The design of the modulator, referred to as the Polyphase Resonant Converter-Modulator takes advantage of high-power component advances, in response to the needs of the traction motor industry (in particular, railroad locomotives), such as Insulated Gate Bipolar Transistors (IGBT's) and self-clearing metallized hazy polypropylene capacitors. In addition, the use of amorphous nanocrystalline transformer core alloy permits high frequency voltage and current transformation with low loss and small size. Other unique concepts embodied in the converter-modulator topology are polyphase resonant voltage multiplication and resonant rectification. These techniques further reduce size and improve electrical efficiency. Because of the resonant conversion techniques, electronic 'crowbars' and other load protective networks are not required. A shorted load detunes the circuit resonance and little power transfer can occur. This yields a high-power, high-voltage system that is inherently self-protective. To provide regulated output voltages, Pulse Width Modulation (PWM) of the individual IGBT pulses is used. A Digital signal Processor (DSP) is used to control the IGBT's, with adaptive feed forward and feedback control algorithms that improve pulse fidelity. The converter-modulator has many attributes that make it attractive to various pulse power and plasma applications such as high power RF sources, neutral beam modulators, and various plasma applications. This paper will review the design as used for the SNS accelerator and speculate on related plasma applications.

  13. Thermal analysis of the ATI thermionic converter for optimum cesium reservoir location

    SciTech Connect (OSTI)

    Young, T.J. (Aerospace Power Division, Wright Laboratory/POOC, Wright-Patterson AFB, Ohio 45433-6563 (United States)); Thayer, K.L.; Ramalingam, M.L. (UES, Inc., 4401 Dayton-Xenia Road, Dayton, Ohio 45432-1894 (United States))

    1993-01-15T23:59:59.000Z

    A first-order thermal analysis was performed on the emitter lead region of the Advanced Thermionic Initiative (ATI) Thermionic Fuel Element (TFE) design. The lead region is the candidate location for a metal-matrix, cesium-graphite reservoir to supply cesium vapor to the thermionic converter. The cesium pressure developed is dependent upon the temperature and cesium-carbon equilibrium reaction of the reservoir. Steady-state, one dimensional conduction, with thermal radiation losses and Joulean heat generation, was used to calculate the temperature distribution in the non-fueled lead region. This temperature distribution was linked to the ATI reactor core design through the integration of axial emitter temperature distributions for the maximum, minimum, and average power TFE fuel pins. The axial temperature distribution in the emitter lead region was found to be most pronounced for the maximum power fuel element and least pronounced for the minimum power TFE.

  14. Droop Compensation with soft Switching for High Voltage Converter Modulator (HVCM)

    SciTech Connect (OSTI)

    Bland, Michael [University of Nottingham; Scheinker, Alexander [Los Alamos National Laboratory; Clare, Jon [University of Nottingham; Watson, Alan [University of Nottingham; Ji, Chao [University of Nottingham; Reass, William [Los Alamos National Laboratory

    2012-06-04T23:59:59.000Z

    High Voltage Converter Modulators (HVCM) offer significant performance advantages over conventional modulator technologies for long pulse applications. One of the key advantages of HVCM technology is the ability to compensate for capacitor bank voltage droop. Achieving droop compensation without incurring significant additional switching loss has not been possible in existing designs. This paper presents an analysis of the 'Y-point' variant of the HVCM topology using the Combined Phase and Frequency Modulation (CPFM) technique. This, combined with the addition of a 'lossless' snubber circuit, enables droop compensation while achieving soft switching over the entire pulse duration. The rise time and overshoot of the output voltage pulse is optimized using an iterative extreme seeking algorithm. The optimization reduces the rise time from 100 {micro}s to 50 {micro}s with no overshoot. This will lead to an increase in overall accelerator efficiency.

  15. Storage of up-converted telecom photons in a doped crystal

    E-Print Network [OSTI]

    Nicolas Maring; Kutlu Kutluer; Joachim Cohen; Matteo Cristiani; Margherita Mazzera; Patrick M. Ledingham; Hugues de Riedmatten

    2014-10-01T23:59:59.000Z

    We report on an experiment that demonstrates the frequency up-conversion of telecommunication wavelength single-photon-level pulses to be resonant with a $\\mathrm{Pr}^{3+}$:$\\mathrm{Y}_2\\mathrm{Si}\\mathrm{O}_5$ crystal. We convert the telecom photons at $1570\\,\\mathrm{nm}$ to $606\\,\\mathrm{nm}$ using a periodically-poled potassium titanyl phosphate nonlinear waveguide. The maximum device efficiency (which includes all optical loss) is inferred to be $\\eta_{\\mathrm{dev}}^{\\mathrm{max}} = 22 \\pm 1\\,%$ (internal efficiency $\\eta_{\\mathrm{int}} = 75\\pm8\\,%$) with a signal to noise ratio exceeding 1 for single-photon-level pulses with durations of up to 560$\\,$ns. The converted light is then stored in the crystal using the atomic frequency comb scheme with storage and retrieval efficiencies exceeding $\\eta_{\\mathrm{AFC}} = 20\\,%$ for predetermined storage times of up to $5\\,\\mu\\mathrm{s}$. The retrieved light is time delayed from the noisy conversion process allowing us to measure a signal to noise ratio exceeding 100 with telecom single-photon-level inputs. These results represent the first demonstration of single-photon-level optical storage interfaced with frequency up-conversion.

  16. First results of the Los Alamos polyphase boost converter-modulator

    SciTech Connect (OSTI)

    Doss, James D.; Gribble, R. F. (Robert F.); Lynch, M. T. (Michael T.); Rees, D. E. (Daniel E.); Tallerico, P. J. (Paul J.); Reass, W. A. (William A.)

    2001-01-01T23:59:59.000Z

    This paper describes the first full-scale electrical test results of the Los Alamos polyphase boost converter-modulator being developed for the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory. The convertrr-modulator provides 140 kV, 1.2 mS, 60 Hz pulses to a 5 MW, 805 MHz klystron. The system, which has 1 MW average power, derives its +/- 1250 Volt DC buss link voltages from a standard 3-phase utility 13.8 kV to 2100 volt transformer. An SCR pre-regulator provides a soft-start function in addition to correction of line and load variations, from no-load to full-load. Energy storage is provided by low inductance self-clearing metallized hazy polypropylene traction capacitors. Each of the 3-phase H-bridge Insulated Gate Bipolar Transistor (IGBT) Pulse-Width Modulation (PWM) drivers are resonated with the amorphous nanocrystalline boost transformer and associated peaking circuits to provide zero-voltage-switching characteristics for the IGBT's. This design feature minimizes IGBT switching losses. By PWM of individual IGBT conduction angles, output pulse regulation with adaptive feedforward and feedback techniques is used to improve the klystron voltage pulse shape. In addition to the first operational results, this paper will discuss the relevant design techniques associated with the boost converter-modulator topology.

  17. Analysis of a transformer-less, multi-level DC-DC converter for HVDC operation

    SciTech Connect (OSTI)

    Karady, G.G.; Devarajan, S. [Arizona State Univ., Tempe, AZ (United States)

    1998-12-31T23:59:59.000Z

    HVDC systems require DC step up and DC step down units. The traditional approach is the application of twelve-pulse thyristor bridges with transformers. The developments of fast switching IGBT devices permit the development of transformer-less, multi-level converters. A multi-level circuit was suggested by Limpaecher. This paper presents a detailed simulation of the proposed circuit together with the analysis of its performance. The converter consists of a set of capacitors, air core inductors and solid state switches arranged in a ladder network. In the step-up mode, the closing of solid state switches resonantly charges the capacitors in parallel through an air-cored inductor. Then solid state switches resonantly charges the capacitors in parallel through an air-cored inductor. Then solid state switches connect the capacitors in series and discharge them through an air-core inductor to the load. In the step-down mode the capacitors are charged in series and discharged in parallel. The circuit has three modes of operation in each cycle: charge, inversion, and discharge. The circuit operation is analyzed in each mode using SPICE simulations. The selection of the components is discussed and output voltage regulation is analyzed. The results show that the proposed circuit promises significant reduction of losses, because of the zero current switching. The investment cost is reduced because of the elimination of transformers.

  18. Radiation heat transfer in multitube, alkaline-metal thermal-to-electric converter

    SciTech Connect (OSTI)

    Tournier, J.M.P.; El-Genk, M.S. [Univ. of New Mexico, Albuquerque, NM (United States)

    1999-02-01T23:59:59.000Z

    Vapor anode, multitube Alkali-Metal Thermal-to-Electric Converters (AMTECs) are being considered for a number of space missions, such as the NASA Pluto/Express (PX) and Europa missions, scheduled for the years 2004 and 2005, respectively. These static converters can achieve a high fraction of Carnot efficiency at relatively low operating temperatures. An optimized cell can potentially provide a conversion efficiency between 20 and 30 percent, when operated at a hot-side temperature of 1000--1200 K and a cold-side temperature of 550--650 K. A comprehensive modeling and testing program of vapor anode, multitube AMTEC cells has been underway for more than three years at the Air Force Research Laboratory`s Power and Thermal Group (AFRL/VSDVP), jointly with the University of New Mexico`s Institute for Space and Nuclear Power Studies. The objective of this program is to demonstrate the readiness of AMTECs for flight on future US Air Force space missions. A fast, integrated AMTEC Performance and Evaluation Analysis Model (APEAM) has been developed to support ongoing vacuum tests at AFRL and perform analyses and investigate potential design changes to improve the PX-cell performance. This model consists of three major components (Tournier and El-Genk 1998a, b): (a) a sodium vapor pressure loss model, which describes continuum, transition and free-molecule flow regimes in the low-pressure cavity of the cell; (b) an electrochemical and electrical circuit model; and (c) a radiation/conduction heat transfer model, for calculating parasitic heat losses. This Technical Note describes the methodology used to calculate the radiation view factors within the enclosure of the PX-cells, and the numerical procedure developed in this work to determine the radiation heat transport and temperatures within the cell cavity.

  19. A Solid Core Heatpipe Reactor with Cylindrical Thermoelectric Converter Modules

    SciTech Connect (OSTI)

    Sayre, Edwin D. [218 Brooke Acres Drive, Los Gatos, CA 95032 (United States); Vaidyanathan, Sam [6663 Pomander Place, San Jose, CA 95120 (United States)

    2006-01-20T23:59:59.000Z

    A nuclear space power system that consists of a solid metal nuclear reactor core with heat pipes carrying energy to a cylindrical thermoelectric converter surrounding each of the heat pipes with a heat pipe radiator surrounding the thermoelectric converter is the most simple and reliable space power system. This means no single point of failure since each heat pipe and cylindrical converter is a separate power system and if one fails it will not affect the others. The heat pipe array in the solid core is designed so that if an isolated heat pipe or even two adjacent heat pipes fail, the remaining heat pipes will still transport the core heat without undue overheating of the uranium nitride fuel. The primary emphasis in this paper is on simplicity, reliability and fabricability of such a space nuclear power source. The core and heat pipes are made of Niobium 1% Zirconium alloy (Nb1Zr), with rhenium lined fuel tubes, bonded together by hot isostatic pressure (HIPing) and with sodium as the heat pipe working fluid, can be operated up to 1250K. The cylindrical thermoelectric converter is made by depositing the constituents of the converter around a Nb1%Zr tube and encasing it in a Nb 1% Zr alloy tube and HIPing the structure to get final bonding and to produce residual compressive stresses in all brittle materials in the converter. A radiator heat pipe filled with potassium that operates at 850K is bonded to the outside of the cylindrical converter for cooling. The solid core heat pipe and cylindrical converter are mated by welding during the final assembly. A solid core reactor with 150 heat pipes with a 0.650-inch (1.65 cm) ID and a 30-inch (76.2 cm) length with an output of 8 Watts per square inch as demonstrated by the SP100 PD2 cell tests will produce about 80 KW of electrical power. An advanced solid core reactor made with molybdenum 47% rhenium alloy, with lithium heat pipes and the PD2 theoretical output of 11 watts per square inch or advanced higher temperature converter to operate at 1350K could produce a greater output of approximately 100KW.

  20. Methods for degrading or converting plant cell wall polysaccharides

    DOE Patents [OSTI]

    Berka, Randy (Davis, CA); Cherry, Joel (Davis, CA)

    2008-08-19T23:59:59.000Z

    The present invention relates to methods for converting plant cell wall polysaccharides into one or more products, comprising: treating the plant cell wall polysaccharides with an effective amount of a spent whole fermentation broth of a recombinant microorganism, wherein the recombinant microorganism expresses one or more heterologous genes encoding enzymes which degrade or convert the plant cell wall polysaccharides into the one or more products. The present invention also relates to methods for producing an organic substance, comprising: (a) saccharifying plant cell wall polysaccharides with an effective amount of a spent whole fermentation broth of a recombinant microorganism, wherein the recombinant microorganism expresses one or more heterologous genes encoding enzymes which degrade or convert the plant cell wall polysaccharides into saccharified material; (b) fermenting the saccharified material of step (a) with one or more fermenting microoganisms; and (c) recovering the organic substance from the fermentation.

  1. DeepWind WP3 D3.32 Technical Report Submersible Converter ........................................................................................................................................................................... 1

    E-Print Network [OSTI]

    Berning, Torsten

    ............................................................................................................................................... 3 2. Test Bench Converter for the 1 kW Floating VAWT Demonstrator

  2. Northwest Energy Innovations (TRL 5 6 System)- WETNZ MtiMode Wave Energy Converter Advancement Project

    Broader source: Energy.gov [DOE]

    Northwest Energy Innovations (TRL 5 6 System) - WETNZ MtiMode Wave Energy Converter Advancement Project

  3. High speed bypass Fig. 1. Sub-module of MMC converter

    E-Print Network [OSTI]

    Chaudhary, Sanjay

    Modular Converter for VSC-HVDC Transmission Applications: Control and Operational Aspects Udana N, the multilevel modular converter (MMC), recently introduced for HVDC transmission are discussed. The paper. Keywords-Voltage Source Convert (VSC), Multilevel Modular Converter (MMC), HVDC Transmission, Weak ac

  4. The important effect of electron reflection on thermionic converter performance

    SciTech Connect (OSTI)

    Rasor, N.S.

    1998-07-01T23:59:59.000Z

    Although only a few percent of high energy electrons are reflected from bare metal surfaces, 20--60% of low energy incident electrons are reflected from thermionic converter electrodes with adsorbed cesium and oxygen. The TECMDL computer model indicates that electron reflection in cesium vapor thermionic converters increases the arc potential drop, offsetting the gain in performance obtainable by lowering the collector work function via the coadsorbed Cs/O layer. The possible suppression of electron reflection by using electrodes with sub-micron surface structure is hypothesized and supported by experimental data obtained by employing a new method for testing in cesium-oxygen vapor.

  5. Process for converting cellulosic materials into fuels and chemicals

    DOE Patents [OSTI]

    Scott, Charles D. (Oak Ridge, TN); Faison, Brendlyn D. (Knoxville, TN); Davison, Brian H. (Knoxville, TN); Woodward, Jonathan (Oak Ridge, TN)

    1994-01-01T23:59:59.000Z

    A process for converting cellulosic materials, such as waste paper, into fuels and chemicals utilizing enzymatic hydrolysis of the major constituent of paper, cellulose. A waste paper slurry is contacted by cellulase in an agitated hydrolyzer. The cellulase is produced from a continuous, columnar, fluidized-bed bioreactor utilizing immobilized microorganisms. An attritor and a cellobiase reactor are coupled to the agitated hydrolyzer to improve reaction efficiency. The cellulase is recycled by an adsorption process. The resulting crude sugars are converted to dilute product in a fluidized-bed bioreactor utilizing microorganisms. The dilute product is concentrated and purified by utilizing distillation and/or a biparticle fluidized-bed bioreactor system.

  6. Method for converting sucrose to .beta.-D-glucose

    DOE Patents [OSTI]

    Simmons, Blake A. (San Francisco, CA); Volponi, Joanne V. (Livermore, CA); Ingersoll, David (Albuquerque, NM); Walker, Andrew (Woodinville, WA)

    2009-07-07T23:59:59.000Z

    Disclosed is an apparatus and method for continuously converting sucrose to .beta.-D-glucose. The method comprises a three-stage enzymatic reactor in which an aqueous solution of sucrose is first converted into a solution of fructose and .alpha.-D-glucose by passing it through a porous, packed column containing an inert media on which invertase is immobilized. This solution is then sent through a second packed column containing glucose isomerase and finally a third packed column containing mutarotase. Solution temperature and pH are adjusted to maximize glucose output.

  7. Modelling, simulation and analysis of low-cost direct torque control of PMSM using hall-effect sensors

    E-Print Network [OSTI]

    Ozturk, Salih Baris

    2007-04-25T23:59:59.000Z

    +steady-state)........................................................175 8.27. Agitation speed control test-bed...................................................................176 8.28. Load torque ( L ), , , and at a 0.35 second ramp time emref emest emact when the PI integrator initial value is 7... N?m................................................182 8.29. s? (Reference Stator Flux), _s est and _s act at a 0.35 second ramp time when the PI integrator initial value is 7 N?m................................................183 8...

  8. Evolution of the angular momentum of protogalaxies from tidal torques: Zel'dovich approximation

    E-Print Network [OSTI]

    Paolo Catelan; Tom Theuns

    1996-04-15T23:59:59.000Z

    The growth of the angular momentum L of protogalaxies induced by tidal torques is reconsidered within the Zel'dovich approximation. We obtain a general expression for the ensemble expectation value of the square of L in terms of the first and second invariant of the inertia tensor of the Lagrangian volume enclosing the protoobject's collapsing mass. We then specialize the formalism to the particular case in which this volume is centered on a peak of the smoothed Gaussian density field and approximated by an isodensity ellipsoid. The result is the appropriate analytical estimate for the rms angular momentum of peaks to be compared against simulations that make use of the Hoffman-Ribak algorithm to set up a constrained density field that contains a peak with given shape. Extending the work of Heavens & Peacock, we calculate the joint probability distribution function for several spin parameters and peak mass M using the distribution of peak shapes, for different initial power spectra. The values of observed specific angular momentum versus mass are well fitted by our theoretical isoprobability contours. In contrast, the observed lower values for the specific angular momentum for ellipticals of the same mass cannot be accounted for within our linear regime investigation, highlighting the importance of strongly non-linear phenomena to explain the spin of such objects.

  9. Observations of thermally excited ferromagnetic resonance on spin torque oscillators having a perpendicularly magnetized free layer

    SciTech Connect (OSTI)

    Tamaru, S., E-mail: shingo.tamaru@aist.go.jp; Kubota, H.; Yakushiji, K.; Konoto, M.; Nozaki, T.; Fukushima, A.; Imamura, H.; Taniguchi, T.; Arai, H.; Tsunegi, S.; Yuasa, S. [Spintronics Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568 (Japan); Suzuki, Y. [Spintronics Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568 (Japan); Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531 (Japan)

    2014-05-07T23:59:59.000Z

    Measurements of thermally excited ferromagnetic resonance were performed on spin torque oscillators having a perpendicularly magnetized free layer and in-plane magnetized reference layer (abbreviated as PMF-STO in the following) for the purpose of obtaining magnetic properties in the PMF-STO structure. The measured spectra clearly showed a large main peak and multiple smaller peaks on the high frequency side. A Lorentzian fit on the main peak yielded Gilbert damping factor of 0.0041. The observed peaks moved in proportion to the out-of-plane bias field. From the slope of the main peak frequency as a function of the bias field, Lande g factor was estimated to be about 2.13. The mode intervals showed a clear dependence on the diameter of the PMF-STOs, i.e., intervals are larger for a smaller diameter. These results suggest that the observed peaks should correspond to eigenmodes of lateral spin wave resonance in the perpendicularly magnetized free layer.

  10. High-efficiency grid-connected photovoltaic module integrated converter system with high-speed communication interfaces for small-scale distribution power generation

    SciTech Connect (OSTI)

    Choi, Woo-Young; Lai, Jih-Sheng (Jason) [Future Energy Electronics Center, Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA (United States)

    2010-04-15T23:59:59.000Z

    This paper presents a high-efficiency grid-connected photovoltaic (PV) module integrated converter (MIC) system with reduced PV current variation. The proposed PV MIC system consists of a high-efficiency step-up DC-DC converter and a single-phase full-bridge DC-AC inverter. An active-clamping flyback converter with a voltage-doubler rectifier is proposed for the step-up DC-DC converter. The proposed step-up DC-DC converter reduces the switching losses by eliminating the reverse-recovery current of the output rectifying diodes. To reduce the PV current variation introduced by the grid-connected inverter, a PV current variation reduction method is also suggested. The suggested PV current variation reduction method reduces the PV current variation without any additional components. Moreover, for centralized power control of distributed PV MIC systems, a PV power control scheme with both a central control level and a local control level is presented. The central PV power control level controls the whole power production by sending out reference power signals to each individual PV MIC system. The proposed step-up DC-DC converter achieves a high-efficiency of 97.5% at 260 W output power to generate the DC-link voltage of 350 V from the PV voltage of 36.1 V. The PV MIC system including the DC-DC converter and the DC-AC inverter achieves a high-efficiency of 95% with the PV current ripple less than 3% variation of the rated PV current. (author)

  11. Turbine tip clearance loss mechanisms

    E-Print Network [OSTI]

    Mazur, Steven (Steven Andrew)

    2013-01-01T23:59:59.000Z

    Three-dimensional numerical simulations (RANS and URANS) were used to assess the impact of two specific design features, and of aspects of the actual turbine environment, on turbine blade tip loss. The calculations were ...

  12. Abstract--An improvement to the precision of losses calculation in static converters used in a hybrid renewable

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    , vaccine storage, rural electrification in developing countries, etc; particularly in isolated places were

  13. Comparison of architectures for two-step flash analog-to-digital converters

    E-Print Network [OSTI]

    Reese, Robert Bryan

    1982-01-01T23:59:59.000Z

    A/D converters have been designed and fabricated in the last three to five ?om a survey of the literature it was discovered that the majority of these converters were of the successive approximation (SAP) type (Table I, page 4). This is because... the SAP converter offers a fast conversion time, a low complexity level and a small area requirement. Only one comparator, the design critical subcircuit of most converters, is needed in a SAP converter. Area requirements increase only moderately...

  14. Introduction to workshop on spectral control and converters

    SciTech Connect (OSTI)

    Wanlass, M.W.; Schwartz, R.J.

    1995-01-05T23:59:59.000Z

    This workshop focused on the portion of the TPV system that involves the photovoltaic energy converter and the spectral control element that affects subband-gap photon energy recovery. The discussion was divided into three major topic areas: status of the technology, status of the infrastructure, and champions of the technology. (AIP) {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  15. Pre-converted nitric oxide gas in catalytic reduction system

    DOE Patents [OSTI]

    Hsiao, M.C.; Merritt, B.T.; Penetrante, B.M.; Vogtlin, G.E.

    1999-04-06T23:59:59.000Z

    A two-stage catalyst comprises an oxidative first stage and a reductive second stage. The first stage is intended to convert NO to NO{sub 2} in the presence of O{sub 2}. The second stage serves to convert NO{sub 2} to environmentally benign gases that include N{sub 2}, CO{sub 2}, and H{sub 2}O. By preconverting NO to NO{sub 2} in the first stage, the efficiency of the second stage for NO{sub x} reduction is enhanced. For example, an internal combustion engine exhaust is connected by a pipe to a first chamber. An oxidizing first catalyst converts NO to NO{sub 2} in the presence of O{sub 2} and includes platinum/alumina, e.g., Pt/Al{sub 2}O{sub 3} catalyst. A flow of hydrocarbons (C{sub x}H{sub y}) is input from a pipe into a second chamber. For example, propene can be used as a source of hydrocarbons. The NO{sub 2} from the first catalyst mixes with the hydrocarbons in the second chamber. The mixture proceeds to a second reduction catalyst that converts NO{sub 2} to N{sub 2}, CO{sub 2}, and H{sub 2}O, and includes a {gamma}-Al{sub 2}O{sub 3}. The hydrocarbons and NO{sub x} are simultaneously reduced while passing through the second catalyst. 9 figs.

  16. A/D Converter Jee-Hwan Ryu

    E-Print Network [OSTI]

    Ryu, Jee-Hwan

    A/D , MUX and REFS update #12;Korea University of Technology and Education ADSC=1 of Technology and Education Korea University of Technology and Education A/D converter #12;Korea University of Technology and Education () AD > -> X = 1 Korea University of Technology and Education AD #12;Korea

  17. Performance Assessment of the Wave Dragon Wave Energy Converter

    E-Print Network [OSTI]

    Hansen, Ren Rydhof

    Performance Assessment of the Wave Dragon Wave Energy Converter Based on the EquiMar Methodology S of the wave energy sector, device developers are called to provide reliable estimates on power performanceMar, Nissum Bredning, Hanstholm, North Sea, Ekofisk, Wave-to-wire, Wave energy. I. INTRODUCTION The wave

  18. Pre-converted nitric oxide gas in catalytic reduction system

    DOE Patents [OSTI]

    Hsiao, Mark C. (Livermore, CA); Merritt, Bernard T. (Livermore, CA); Penetrante, Bernardino M. (San Ramon, CA); Vogtlin, George E. (Fremont, CA)

    1999-01-01T23:59:59.000Z

    A two-stage catalyst comprises an oxidative first stage and a reductive second stage. The first stage is intended to convert NO to NO.sub.2 in the presence of O.sub.2. The second stage serves to convert NO.sub.2 to environmentally benign gases that include N2, CO2, and H.sub.2 O. By preconverting NO to NO.sub.2 in the first stage, the efficiency of the second stage for NO.sub.x reduction is enhanced. For example, an internal combustion engine exhaust is connected by a pipe to a first chamber. An oxidizing first catalyst converts NO to NO.sub.2 in the presence of O.sub.2 and includes platinum/alumina, e.g., Pt/Al.sub.2 O.sub.3 catalyst. A flow of hydrocarbons (C.sub.x H.sub.y) is input from a pipe into a second chamber. For example, propene can be used as a source of hydrocarbons. The NO.sub.2 from the first catalyst mixes with the hydrocarbons in the second chamber. The mixture proceeds to a second reduction catalyst that converts NO.sub.2 to N2, CO2, and H.sub.2 O, and includes a gamma-alumina .gamma.-Al.sub.2 O.sub.3. The hydrocarbons and NO.sub.x are simultaneously reduced while passing through the second catalyst.

  19. Simulation Model for UltrasonicMotors powered by Resonant Converters

    E-Print Network [OSTI]

    Paderborn, Universität

    of the stator, producing a traveling wave. This process can be assumed as a linear phenomenon. In a second for the drive. Based on recent mechanical approaches in modelingthe stator under considerationof unsymmetriesand-modeapproximationof the stator and piezoceramic. Incorporation of a converter model into the mechanicalsubsystem a proper

  20. Coupled Dual Interleaved Flyback Converter for High Input Voltage Application

    E-Print Network [OSTI]

    Lehman, Brad

    components, including transformers and inductors, significantly influences the overall profiles magnetic core to store the energy in the power transformer. A Flyback converter is a popular choice for low. All the center and outer legs are gapped, and the transformers are integrated into one magnetic core

  1. Soft switched high frequency ac-link converter

    E-Print Network [OSTI]

    Balakrishnan, Anand Kumar

    2009-05-15T23:59:59.000Z

    topology for medium and high power ac-ac, ac-dc and dc-ac applications. An ac-link formed by an inductor-capacitor pair replaces the conventional dc-link. Each leg of the converter is formed by two bidirectional switches. Power transfer from input to output...

  2. Energy Savings Assessment for Digital-to-Analog Converter Boxes

    SciTech Connect (OSTI)

    Cheung, Hoi Ying Iris; Meier, Alan; Brown, Richard

    2011-01-18T23:59:59.000Z

    The Digital Television (DTV) Converter Box Coupon Program was administered by the U.S. government to subsidize purchases of digital-to-analog converter boxes, with up to two $40 coupons for each eligible household. In order to qualify as Coupon Eligible Converter Boxes (CECBs), these devices had to meet a number of minimum performance specifications, including energy efficiency standards. The Energy Star Program also established voluntary energy efficiency specifications that are more stringent than the CECB requirements. In this study, we measured the power and energy consumptions for a sample of 12 CECBs (including 6 Energy Star labeled models) in-use in homes and estimated aggregate energy savings produced by the energy efficiency policies. Based on the 35 million coupons redeemed through the end of the program, our analysis indicates that between 2500 and 3700 GWh per year are saved as a result of the energy efficiency policies implemented on digital-to-analog converter boxes. The energy savings generated are equivalent to the annual electricity use of 280,000 average US homes.

  3. "Black Box" EMC model for Power Electronics Converter Mikael Foissac

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    "Black Box" EMC model for Power Electronics Converter Mikael Foissac Grenoble Electrical be forecasted accurately, in order to avoid disturbance of the complete system. To quantify the EMC behaviour will then illustrate the method on a complete chopper cell. II. BLACK BOX EMC MODEL Any EMC analysis must account

  4. A summary of North American HVDC converter station reliability specifications

    SciTech Connect (OSTI)

    Vancers, I. (ABB Power Systems Inc., Los Angeles, CA (United States)); Hormozi, F.J. (Los Angeles Dept. of Water and Power, CA (United States))

    1993-07-01T23:59:59.000Z

    This paper summarizes Reliability, Availability, and Maintainability (RAM) specifications that were issued for thyristor based HVDC converter stations in service in North America. A total of twenty project specifications are summarized. A detailed summary by project is shown with specific quantitative requirements categorized. Definitions of terms, representative design principles, and formulas used in calculating RAM parameters contained in existing reliability specifications are presented.

  5. INVERSION OF CONVERTED-WAVE SEISMIC DATA FOR RESERVOIR CHARACTERIZATION

    E-Print Network [OSTI]

    INVERSION OF CONVERTED-WAVE SEISMIC DATA FOR RESERVOIR CHARACTERIZATION AT RULISON FIELD, COLORADO Basin of northwest Colorado. The reservoir consists of lenticular fluvial sands, shales, and coals of magnitude lower than the seismic resolution which is 105 ft. The sandstone reservoirs are the primary target

  6. OPERATIONAL RESULTS OF THE SPALLATION NEUTRON SOURCE (SNS) POLYPHASE CONVERTER-MODULATOR FOR THE 140 KV KLYSTRON RF SYSTEMS

    SciTech Connect (OSTI)

    W.A. REASS; J.D. DOSS; ET AL

    2001-06-01T23:59:59.000Z

    This paper describes the first operational results of the 140 kV, 1 MW average, 11 MW peak, zero-voltage-switching, 20 kHz polyphase bridge, boost converter-modulator for klystron pulse application. The DC-DC converter derives the buss voltages from a standard 13.8 kV to 2100 Y substation cast-core transformer. Energy storage and filtering is provided by self-clearing metallized hazy polypropylene traction capacitors. Three ''H-Bridge'' Insulated Gate Bipolar Transistor (IGBT) switching networks are used to generate the polyphase 20 kHz transformer primary drive waveforms. The 20 kHz drive waveforms are chirped the appropriate duration to generate the desired klystron pulse width. Pulse-Width Modulation (PWM) of the individual 20 kHz pulses is utilized to provide regulated output waveforms with adaptive feedforward and feedback techniques. The boost transformer design utilizes amorphous nanocrystalline material that provides the required low core loss at design flux levels and switching frequencies. Resonant shunt peaking is used on the transformer secondary to boost output voltage and resonate transformer leakage inductance. With the appropriate transformer leakage inductance and peaking capacitance, zero-voltage-switching of the IGBT's is attained, minimizing switching losses. Reviews of these design parameters and an examination of the first operational results will be performed.

  7. Operational results of the spallation neutron source (SNS) polyphase converter-modulator for the 140 KV klystron RF system

    SciTech Connect (OSTI)

    Reass, W. A. (William A.); Doss, James D.; Gribble, R. F. (Robert F.); Lynch, M. T. (Michael T.); Rees, D. E. (Daniel E.); Tallerico, P. J. (Paul J.); Borovina, D. L.

    2001-01-01T23:59:59.000Z

    This paper describes the first operational results of the 140 kV, 1 MW average, 11 MW peak, zero-voltageswitching, 20 kHz polyphase bridge, boost converter-modulator for klystron pulse application. The DC-DC converter derives the buss voltages from a standard 13.8 kV to 2100 Y substation cast-core transformer. Energy storage and filtering is provided by self-clearing metallized hazy polypropylene traction capacitors. Three 'H-Bridge' Insulated Gate Bipolar Transistor (IGBT) switching networks are used to generate the polyphase 20 kHz transformer primary drive waveforms. The 20 kHz drive waveforms are chirped the appropriate duration to generate the desired klystron pulse width. Pulse-Width Modulation (PWM) of the individual 20 kHz pulses is utilized to provide regulated output waveforms with adaptive feedforward and feedback techniques. The boost transformer design utilizes amorphous nanocrystalline material that provides the required low core loss at design flux levels and switching frequencies. Resonant shunt peaking is used on the transformer secondary to boost output voltage and resonate transformer leakage inductance. With the appropriate transformer leakage inductance and peaking capacitance, zero-voltage-switching of the IGBT's is attained, minimizing switching losses. Reviews of these design parameters and an examination of the first operational results will be performed.

  8. Efficiency loss in resource allocation games

    E-Print Network [OSTI]

    Xu, Yunjian

    2012-01-01T23:59:59.000Z

    The overarching goals of this thesis are to quantify the efficiency loss due to market participant strategic behavior, and to design proper pricing mechanisms that reduce the efficiency loss. The concept of efficiency loss ...

  9. Cancer Vulnerabilities Unveiled by Genomic Loss

    E-Print Network [OSTI]

    Nijhawan, Deepak

    Due to genome instability, most cancers exhibit loss of regions containing tumor suppressor genes and collateral loss of other genes. To identify cancer-specific vulnerabilities that are the result of copy number losses, ...

  10. Cryogenic loss monitors with FPGA TDC signal processing

    E-Print Network [OSTI]

    Warner, A

    2012-01-01T23:59:59.000Z

    Radiation hard helium gas ionization chambers capable of operating in vacuum at temperatures ranging from 5K to 350K have been designed, fabricated and tested and will be used inside the cryostats at Fermilab's Superconducting Radiofrequency beam test facility. The chamber vessels are made of stainless steel and all materials used including seals are known to be radiation hard and suitable for operation at 5K. The chambers are designed to measure radiation up to 30 kRad/hr with sensitivity of approximately 1.9 pA/(Rad/hr). The signal current is measured with a recycling integrator current-to-frequency converter to achieve a required measurement capability for low current and a wide dynamic range. A novel scheme of using an FPGA-based time-to-digital converter (TDC) to measure time intervals between pulses output from the recycling integrator is employed to ensure a fast beam loss response along with a current measurement resolution better than 10-bit. This paper will describe the results obtained and highligh...

  11. Cryogenic loss monitors with FPGA TDC signal processing

    SciTech Connect (OSTI)

    Warner, A.; Wu, J.; /Fermilab

    2011-09-01T23:59:59.000Z

    Radiation hard helium gas ionization chambers capable of operating in vacuum at temperatures ranging from 5K to 350K have been designed, fabricated and tested and will be used inside the cryostats at Fermilab's Superconducting Radiofrequency beam test facility. The chamber vessels are made of stainless steel and all materials used including seals are known to be radiation hard and suitable for operation at 5K. The chambers are designed to measure radiation up to 30 kRad/hr with sensitivity of approximately 1.9 pA/(Rad/hr). The signal current is measured with a recycling integrator current-to-frequency converter to achieve a required measurement capability for low current and a wide dynamic range. A novel scheme of using an FPGA-based time-to-digital converter (TDC) to measure time intervals between pulses output from the recycling integrator is employed to ensure a fast beam loss response along with a current measurement resolution better than 10-bit. This paper will describe the results obtained and highlight the processing techniques used.

  12. Low work function material development for the microminiature thermionic converter.

    SciTech Connect (OSTI)

    Zavadil, Kevin Robert; Battaile, Corbett Chandler; Marshall, Albert Christian; King, Donald Bryan; Jennison, Dwight Richard

    2004-03-01T23:59:59.000Z

    Thermionic energy conversion in a miniature format shows potential as a viable, high efficiency, micro to macro-scale power source. A microminiature thermionic converter (MTC) with inter-electrode spacings on the order of microns has been prototyped and evaluated at Sandia. The remaining enabling technology is the development of low work function materials and processes that can be integrated into these converters to increase power production at modest temperatures (800 - 1300 K). The electrode materials are not well understood and the electrode thermionic properties are highly sensitive to manufacturing processes. Advanced theoretical, modeling, and fabrication capabilities are required to achieve optimum performance for MTC diodes. This report describes the modeling and fabrication efforts performed to develop micro dispenser cathodes for use in the MTC.

  13. Process for converting cellulosic materials into fuels and chemicals

    DOE Patents [OSTI]

    Scott, C.D.; Faison, B.D.; Davison, B.H.; Woodward, J.

    1994-09-20T23:59:59.000Z

    A process is described for converting cellulosic materials, such as waste paper, into fuels and chemicals utilizing enzymatic hydrolysis of the major constituent of paper, cellulose. A waste paper slurry is contacted by cellulase in an agitated hydrolyzer. The cellulase is produced from a continuous, columnar, fluidized-bed bioreactor utilizing immobilized microorganisms. An attrition mill and a cellobiase reactor are coupled to the agitated hydrolyzer to improve reaction efficiency. The cellulase is recycled by an adsorption process. The resulting crude sugars are converted to dilute product in a fluidized-bed bioreactor utilizing microorganisms. The dilute product is concentrated and purified by utilizing distillation and/or a biparticle fluidized-bed bioreactor system. 1 fig.

  14. Planar LTCC transformers for high voltage flyback converters: Part II.

    SciTech Connect (OSTI)

    Schofield, Daryl (NASCENTechnology, Inc., Watertown, SD); Schare, Joshua M., Ph.D.; Slama, George (NASCENTechnology, Inc., Watertown, SD); Abel, David (NASCENTechnology, Inc., Watertown, SD)

    2009-02-01T23:59:59.000Z

    This paper is a continuation of the work presented in SAND2007-2591 'Planar LTCC Transformers for High Voltage Flyback Converters'. The designs in that SAND report were all based on a ferrite tape/dielectric paste system originally developed by NASCENTechnoloy, Inc, who collaborated in the design and manufacturing of the planar LTCC flyback converters. The output/volume requirements were targeted to DoD application for hard target/mini fuzing at around 1500 V for reasonable primary peak currents. High voltages could be obtained but with considerable higher current. Work had begun on higher voltage systems and is where this report begins. Limits in material properties and processing capabilities show that the state-of-the-art has limited our practical output voltage from such a small part volume. In other words, the technology is currently limited within the allowable funding and interest.

  15. Discharging a DC bus capacitor of an electrical converter system

    DOE Patents [OSTI]

    Kajouke, Lateef A; Perisic, Milun; Ransom, Ray M

    2014-10-14T23:59:59.000Z

    A system and method of discharging a bus capacitor of a bidirectional matrix converter of a vehicle are presented here. The method begins by electrically shorting the AC interface of the converter after an AC energy source is disconnected from the AC interface. The method continues by arranging a plurality of switching elements of a second energy conversion module into a discharge configuration to establish an electrical current path from a first terminal of an isolation module, through an inductive element, and to a second terminal of the isolation module. The method also modulates a plurality of switching elements of a first energy conversion module, while maintaining the discharge configuration of the second energy conversion module, to at least partially discharge a DC bus capacitor.

  16. Development, evaluation, and design applications of an AMTEC converter model

    E-Print Network [OSTI]

    Spence, Cliff Alan

    2002-01-01T23:59:59.000Z

    of performance curves . . . . . . . 90 INTRODUCTION In the recent history of space exploration, space vehicles slated for missions that ventured into deep space, far from the sun, typically relied on Radioisotope Thermoelectric Generator (RTG) power sources... this need is a type of generator that uses technology known as alkali metal thermal-to-electric conversion (AMTEC). This device, like previous thermoelectric power systems, converts thermal energy directly to electricity. Developed at Ford Scientific...

  17. Capacitor-Less VAR Compensator Based on a Matrix Converter

    E-Print Network [OSTI]

    Balakrishnan, Divya Rathna

    2012-02-14T23:59:59.000Z

    greatly contributed to the completion of this work. I owe my gratitude to them for always believing in me and helping me through my academic pursuit. vii NOMENCLATURE VAR Volt-ampere reactive MC 3-phase ac-to-3-phase ac matrix converter v1... [10] ...... 12 10 Equivalent circuit of a capacitor................................................................. 13 11 Basic layout of a 3/3 MC............................................................................ 16 12 Block diagram...

  18. Low current plasmatron fuel converter having enlarged volume discharges

    DOE Patents [OSTI]

    Rabinovich, Alexander (Swampscott, MA); Alexeev, Nikolai (Moscow, RU); Bromberg, Leslie (Sharon, MA); Cohn, Daniel R. (Chestnut Hill, MA); Samokhin, Andrei (Moscow, RU)

    2009-10-06T23:59:59.000Z

    A novel apparatus and method is disclosed for a plasmatron fuel converter ("plasmatron") that efficiently uses electrical energy to produce hydrogen rich gas. The volume and shape of the plasma discharge is controlled by a fluid flow established in a plasma discharge volume. A plasmatron according to this invention produces a substantially large effective plasma discharge volume allowing for substantially greater volumetric efficiency in the initiation of chemical reactions within a volume of bulk fluid reactant flowing through the plasmatron.

  19. Intensive neutrino source on the base of lithium converter

    E-Print Network [OSTI]

    V. I. Lyashuk; Yu. S Lutostansky

    2015-04-13T23:59:59.000Z

    An intensive antineutrino source with a hard spectrum (with energy up to 13 MeV, average energy 6.5 MeV) can be realized on the base of beta-decay of short living isotope 8Li (0.84 s). The 8Li isotope (generated in activation of 7Li isotope) is a prime perspective antineutrino source owing to the hard antineutrino spectrum and square dependence of cross section on the energy. Up today nuclear reactors are the most intensive neutrino sources. Antineutrino reactor spectra have large uncertainties in the summary antineutrino spectrum at energy E>6 MeV. Use of 8Li isotope allows to decrease sharply the uncertainties or to exclude it completely. An intensive neutron fluxes are requested for rapid generation of 8Li isotope. The installations on the base of nuclear reactors can be an alternative for nuclear reactors as traditional neutron sources. It is possible creation of neutrino sources another in principle: on the base of tandem of accelerators, neutron generating targets and lithium converter. An intensive neutron flux (i.e., powerful neutron source) is requested for realization of considered neutrino sources (neutrino factories). Different realizations of lithium antineutrino sources (lithium converter on the base of high purified 7Li isotope) are discussed: static regime (i.e., without transport of 8Li isotope to the neutrino detector); dynamic regime (transport of 8Li isotope to the remote detector in a closed cycle); an operation of lithium converter in tandem of accelerator with a neutron-producing target on the base of tungsten, lead or bismuth. Different chemical compounds of lithium (as the substance of the converter) are considered. Heavy water solution of LiOD is proposed as a serious alternative to high-pure 7Li in a metallic state.

  20. Low current plasmatron fuel converter having enlarged volume discharges

    DOE Patents [OSTI]

    Rabinovich, Alexander; Alexeev, Nikolai; Bromberg, Leslie; Cohn, Daniel R.; Samokhin, Andrei

    2005-04-19T23:59:59.000Z

    A novel apparatus and method is disclosed for a plasmatron fuel converter (""plasmatron"") that efficiently uses electrical energy to produce hydrogen rich gas. The volume and shape of the plasma discharge is controlled by a fluid flow established in a plasma discharge volume. A plasmatron according to this invention produces a substantially large effective plasma discharge volume allowing for substantially greater volumetric efficiency in the initiation of chemical reactions within a volume of bulk fluid reactant flowing through the plasmatron.

  1. Liquid Metal Thermal Electric Converter bench test module

    SciTech Connect (OSTI)

    Lukens, L.L.; Andraka, C.E.; Moreno, J.B.

    1988-04-01T23:59:59.000Z

    This report describes the design, fabrication, and test of a Liquid Metal Thermal Electric Converter Bench Test Module. The work presented in this document was conducted as a part of Heat Engine Task of the US Department of Energy's (DOE) Solar Thermal Technology Program. The objective of this task is the development and evaluation of heat engine technologies applicable to distributed receiver systems, in particular, dish electric systems.

  2. Intensive neutrino source on the base of lithium converter

    E-Print Network [OSTI]

    V. I. Lyashuk; Yu. S Lutostansky

    2015-03-04T23:59:59.000Z

    An intensive antineutrino source with a hard spectrum (with energy up to 13 MeV, average energy 6.5 MeV) can be realized on the base of beta-decay of short living isotope 8Li (0.84 s). The 8Li isotope (generated in activation of 7Li isotope) is a prime perspective antineutrino source owing to the hard antineutrino spectrum and square dependence of cross section on the energy. Up today nuclear reactors are the most intensive neutrino sources. Antineutrino reactor spectra have large uncertainties in the summary antineutrino spectrum at energy E>6 MeV. Use of 8Li isotope allows to decrease sharply the uncertainties or to exclude it completely. An intensive neutron fluxes are requested for rapid generation of 8Li isotope. The installations on the base of nuclear reactors can be an alternative for nuclear reactors as traditional neutron sources. It is possible creation of neutrino sources another in principle: on the base of tandem of accelerators, neutron generating targets and lithium converter. An intensive neutron flux (i.e., powerful neutron source) is requested for realization of considered neutrino sources (neutrino factories). Different realizations of lithium antineutrino sources (lithium converter on the base of high purified 7Li isotope) are discussed: static regime (i.e., without transport of 8Li isotope to the neutrino detector); dynamic regime (transport of 8Li isotope to the remote detector in a closed cycle); an operation of lithium converter in tandem of accelerator with a neutron-producing target on the base of tungsten, lead or bismuth. Different chemical compounds of lithium (as the substance of the converter) are considered. Heavy water solution of LiOD is proposed as a serious alternative to high-pure 7Li in a metallic state.

  3. Catalyst for converting synthesis gas to liquid motor fuels

    DOE Patents [OSTI]

    Coughlin, Peter K. (Yorktown Heights, NY)

    1986-01-01T23:59:59.000Z

    The addition of an inert metal component, such as gold, silver or copper, to a Fischer-Tropsch catalyst comprising cobalt enables said catalyst to convert synthesis gas to liquid motor fuels at about 240.degree.-370.degree. C. with advantageously reduced selectivity of said cobalt for methane in said conversion. The catalyst composition can advantageously include a support component, such as a molecular sieve, co-catalyst/support component or a combination of such support components.

  4. Enhanced synchronization in an array of spin torque nano oscillators in the presence of oscillating external magnetic field

    E-Print Network [OSTI]

    B. Subash; V. K. Chandrasekar; M. Lakshmanan

    2014-12-23T23:59:59.000Z

    We demonstrate that the synchronization of an array of electrically coupled spin torque nano-oscillators (STNO) modelled by Landau-Lifshitz-Gilbert-Slonczewski (LLGS) equation can be enhanced appreciably in the presence of a common external microwave magnetic field. The applied microwave magnetic field stabilizes and enhances the regions of synchronization in the parameter space of our analysis, where the oscillators are exhibiting synchronized oscillations thereby emitting improved microwave power. To characterize the synchronized oscillations we have calculated the locking range in the domain of external source frequency.

  5. Power Maximization in Wave-Energy Converters Using Sampled -Data Extremum Seeking /

    E-Print Network [OSTI]

    Chen, Tianjia

    2013-01-01T23:59:59.000Z

    design optimization of wave energy converters con- sistingN. Sahinkaya. A review of wave energy converter technology.2009. [6] A.F.O. Falcao. Wave energy utilization: A review

  6. Blind calibration of timing skew in time-interleaved analog-to-digital converters

    E-Print Network [OSTI]

    Divi, Vijay

    The performance of time-interleaved analog-to-digital converters is often significantly degraded by timing mismatch errors. We develop methods for performing blind calibration of such converters, i.e., for estimating the ...

  7. Computer-aided optimization of DC/DC converters for automotive applications

    E-Print Network [OSTI]

    Neugebauer, Timothy C.

    This paper investigates computer-aided optimization of DC/DC converters, with a focus on converters for dual-voltage automotive electrical systems. A new CAD optimization approach based on Monte Carlo search methods is ...

  8. CHARACTERIZING DANGEROUS WAVES FOR OCEAN WAVE ENERGY CONVERTER SURVIVABILITY Justin Hovland

    E-Print Network [OSTI]

    Haller, Merrick

    CHARACTERIZING DANGEROUS WAVES FOR OCEAN WAVE ENERGY CONVERTER SURVIVABILITY Justin Hovland ABSTRACT Ocean Wave Energy Converters (OWECs) operating on the water surface are subject to storms at station 139. Keywords: wave energy, survivability, breaking waves, joint distribution, OWEC INTRODUCTION

  9. Characterization of U.S. Wave Energy Converter Test Sites: A...

    Energy Savers [EERE]

    Characterization of U.S. Wave Energy Converter Test Sites: A Catalogue of Met-Ocean Data Characterization of U.S. Wave Energy Converter Test Sites: A Catalogue of Met-Ocean Data...

  10. Report of the DOD-DOE Workshop on Converting Waste to Energy...

    Office of Environmental Management (EM)

    DOD-DOE Workshop on Converting Waste to Energy Using Fuel Cells: Workshop Summary and Action Plan Report of the DOD-DOE Workshop on Converting Waste to Energy Using Fuel Cells:...

  11. Charm Quark Energy Loss in QCD Matter

    E-Print Network [OSTI]

    W. C. Xiang; H. T. Ding; D. C. Zhou; D. Rohrich

    2005-07-13T23:59:59.000Z

    The energy loss of heavy quarks in a quark-gluon plasma of finite size is studied within the light-cone integral approach. A simple analytical formulation of the radiative energy loss of heavy quarks is derived. This provides a convenient way to quantitatively estimate the quark energy loss. Our results show that if the energy of a heavy quark is much larger than its mass, the radiative energy loss approaches the radiative energy loss of light quarks.

  12. Comparison between arc drops in ignited thermionic converters with and without ion reflections at the emitter

    SciTech Connect (OSTI)

    Lundgren, L.

    1985-07-01T23:59:59.000Z

    The output performance of two thermionic energy converters is compared. One converter has a normal emitter, working with zero field at the emitter which is close to the optimum working point, and the other has a low work function emitter and ion reflection at the emitter. A simple model of the plasma and the sheaths shows that a converter working with a low work function emitter and ion reflections gives a worse performance than a similar converter with a normal emitter.

  13. Reentry aerodynamic disruption analysis of thermionic reactor-thermo-converter TOPAZ-2

    SciTech Connect (OSTI)

    Grinberg, E.I.; Nikolaev, V.S. (Scientific Production Association Krasnaya Zvezda'', Moscow 115230 (Russian Federation)); Usov, V.A. (RRC Kurchatov Institute'', Moscow 123182 (Russian Federation)); Gafarov, A.A. (Research Institute of Thermal Processes, Moscow (Russian Federation))

    1993-01-15T23:59:59.000Z

    This paper presents preliminary results of analysis for the TOPAZ-2 thermionic converter-reactor aerodynamic disruption during reentry.

  14. Predictive Power Control of Doubly-Fed Induction Generator for Wave Energy Converters

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    Predictive Power Control of Doubly-Fed Induction Generator for Wave Energy Converters M.S. Lagoun1. There are several wave energy converters to harness this energy. Some of them, as in tidal applications, use of a DFIG-based Wave Energy Converter (WEC). In the proposed control approach, the predicted output power

  15. A Predictive power control of Doubly Fed Induction Generator for Wave Energy Converter

    E-Print Network [OSTI]

    Brest, Universit de

    A Predictive power control of Doubly Fed Induction Generator for Wave Energy Converter in Irregular there are several wave energy converters to harness this energy. Some of them, as in tidal applications, use based Wave Energy Converter under irregular wave climate which is modeled as time series elevation from

  16. Modeling and Analysis of Hybrid Converters Michael Evzelman Shmuel (Sam) Ben-Yaakov

    E-Print Network [OSTI]

    the characteristics of hybrid converters. Renewable energy sources such as a single PV panel have, in general, a lowModeling and Analysis of Hybrid Converters Michael Evzelman Shmuel (Sam) Ben-Yaakov Power.ee.bgu.ac.il/~pel/ Abstract--A generic behavioral average-circuit model that analyzes hybrid converters that include

  17. Design techniques for low noise and high speed A/D converters

    E-Print Network [OSTI]

    Gupta, Amit Kumar

    2009-05-15T23:59:59.000Z

    . The resolution and sampling rate of an A/D converter vary depending on the application. Recently, there has been a growing demand for broadband (>1 MHz), high-resolution (>14bits) A/D converters. Applications that demand such converters include asymmetric digital...

  18. High Efficiency Interleaved Power Electronics Converter for wide operating power range

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    High Efficiency Interleaved Power Electronics Converter for wide operating power range K driving strategy for improving the efficiency of power converters even if they are not used is presented. Index Terms-Power converters, Interleaved, Power efficiency I. CONTEXTE, INTRODUCTION One

  19. Design techniques for low noise and high speed A/D converters

    E-Print Network [OSTI]

    Gupta, Amit Kumar

    2009-05-15T23:59:59.000Z

    . The resolution and sampling rate of an A/D converter vary depending on the application. Recently, there has been a growing demand for broadband (>1 MHz), high-resolution (>14bits) A/D converters. Applications that demand such converters include asymmetric digital...

  20. Development of a 55 kW 3X DC-DC Converter for HEV Systems

    E-Print Network [OSTI]

    Tolbert, Leon M.

    converter and a traction motor to drive the vehicle. In most commercial HEV systems, the power converter one of the hottest parts in the system. Hence, with the trend of higher coolant temperatures, those-dc converter and the continuous control of the modulation index of the inverter, it is sufficient to operate

  1. Macrospin modeling of sub-ns pulse switching of perpendicularly magnetized free layer via spin-orbit torques for cryogenic memory applications

    SciTech Connect (OSTI)

    Park, Junbo; Rowlands, G. E.; Lee, O. J.; Buhrman, R. A. [Cornell University, Ithaca, New York 14853 (United States); Ralph, D. C. [Cornell University, Ithaca, New York 14853 (United States); Kavli Institute at Cornell, Ithaca, New York 14853 (United States)

    2014-09-08T23:59:59.000Z

    We model, using the macrospin approximation, the magnetic reversal of a perpendicularly magnetized nanostructured free layer formed on a normal, heavy-metal nanostrip, subjected to spin-orbit torques (SOTs) generated by short (?0.5?ns) current pulses applied to the nanostrip, to examine the potential for SOT-based fast, efficient cryogenic memory. Due to thermal fluctuations, if solely an anti-damping torque is applied, then, for a device with sufficiently low anisotropy (H{sub anis}{sup 0}???1 kOe) suitable for application in cryogenic memory, a high magnetic damping parameter (??0.1?0.2) is required for reliable switching over a significant variation of pulse current. The additional presence of a substantial field-like torque improves switching reliability even for low damping (??0.03).

  2. Combined Effects of Gravity, Bending Moment, Bearing Clearance, and Input Torque on Wind Turbine Planetary Gear Load Sharing: Preprint

    SciTech Connect (OSTI)

    Guo, Y.; Keller, J.; LaCava, W.

    2012-09-01T23:59:59.000Z

    This computational work investigates planetary gear load sharing of three-mount suspension wind turbine gearboxes. A three dimensional multibody dynamic model is established, including gravity, bending moments, fluctuating mesh stiffness, nonlinear tooth contact, and bearing clearance. A flexible main shaft, planetary carrier, housing, and gear shafts are modeled using reduced degrees-of-freedom through modal compensation. This drivetrain model is validated against the experimental data of Gearbox Reliability Collaborative for gearbox internal loads. Planet load sharing is a combined effect of gravity, bending moment, bearing clearance, and input torque. Influences of each of these parameters and their combined effects on the resulting planet load sharing are investigated. Bending moments and gravity induce fundamental excitations in the rotating carrier frame, which can increase gearbox internal loads and disturb load sharing. Clearance in carrier bearings reduces the bearing load carrying capacity and thus the bending moment from the rotor can be transmitted into gear meshes. With bearing clearance, the bending moment can cause tooth micropitting and can induce planet bearing fatigue, leading to reduced gearbox life. Planet bearings are susceptible to skidding at low input torque.

  3. Evaluation of the toroidal torque driven by external non-resonant non-axisymmetric magnetic field perturbations in a tokamak

    SciTech Connect (OSTI)

    Kasilov, Sergei V. [Fusion@AW, Institut fr Theoretische PhysikComputational Physics, Technische Universitt Graz Petersgasse 16, A8010 Graz (Austria); Institute of Plasma Physics National Science Center Kharkov Institute of Physics and Technology ul. Akademicheskaya 1, 61108 Kharkov (Ukraine); Kernbichler, Winfried; Martitsch, Andreas F.; Heyn, Martin F. [Fusion@AW, Institut fr Theoretische PhysikComputational Physics, Technische Universitt Graz Petersgasse 16, A8010 Graz (Austria); Maassberg, Henning [Max-Planck Institut fr Plasmaphysik, D-17491 Greifswald (Germany)

    2014-09-15T23:59:59.000Z

    The toroidal torque driven by external non-resonant magnetic perturbations (neoclassical toroidal viscosity) is an important momentum source affecting the toroidal plasma rotation in tokamaks. The well-known force-flux relation directly links this torque to the non-ambipolar neoclassical particle fluxes arising due to the violation of the toroidal symmetry of the magnetic field. Here, a quasilinear approach for the numerical computation of these fluxes is described, which reduces the dimension of a standard neoclassical transport problem by one without model simplifications of the linearized drift kinetic equation. The only limiting condition is that the non-axisymmetric perturbation field is small enough such that the effect of the perturbation field on particle motion within the flux surface is negligible. Therefore, in addition to most of the transport regimes described by the banana (bounce averaged) kinetic equation also such regimes as, e.g., ripple-plateau and resonant diffusion regimes are naturally included in this approach. Based on this approach, a quasilinear version of the code NEO-2 [W. Kernbichler et al., Plasma Fusion Res. 3, S1061 (2008).] has been developed and benchmarked against a few analytical and numerical models. Results from NEO-2 stay in good agreement with results from these models in their pertinent range of validity.

  4. Design and analysis of modern three-phase AC/AC power converters for AC drives and utility interface

    E-Print Network [OSTI]

    Kwak, Sangshin

    2005-08-29T23:59:59.000Z

    Significant advances in modern ac/ac power converter technologies and demands of industries have reached beyond standard ac/ac power converters with voltage-source inverters fed from diode rectifiers. Power electronics converters have been matured...

  5. The Effects of Stator Compliance, Backs Steps, Temperature, and Clockwise Rotation on the Torque-Speed Curve of Bacterial Flagellar Motor

    E-Print Network [OSTI]

    Giovanni Meacci; Ganhui Lan; Yuhai Tu

    2010-08-13T23:59:59.000Z

    Rotation of a single bacterial flagellar motor is powered by multiple stators tethered to the cell wall. In a "power-stroke" model the observed independence of the speed at low load on the number of stators is explained by a torque-dependent stepping mechanism independent of the strength of the stator tethering spring. On the other hand, in models that depend solely on the stator spring to explain the observed behavior, exceedingly small stator spring constants are required. To study the dynamics of the motor driven by external forces (such as those exerted by an optical tweezer), back-stepping is introduced when stators are driven far out of equilibrium. Our model with back-stepping reproduces the observed absence of a barrier to backward rotation, as well the behaviors in the high-speed negative-torque regime. Recently measured temperature dependence of the motor speed near zero load (Yuan & Berg 2010 Biophys J) is explained quantitatively by the thermally activated stepping rates in our model. Finally, we suggest that the general mechanical properties of all molecular motors (linear and rotary), characterized by their force(torque)-speed curve, can be determined by their power-stroke potentials and the dependence of the stepping rates on the mechanical state of the motor (force or speed). The torque-speed curve for the clockwise rotating flagellar motor has been observed for the first time recently (Yuan et al. 2010 PNAS). Its quasi-linear behavior is quantitatively reproduced by our model. In particular, we show that concave and convex shapes of the torque-speed curve can be achieved by changing the interaction potential from linear to quadratic form. We also show that reversing the stepping rate dependence on force (torque) can lead to non-monotonicity in the speed-load dependency.

  6. The mathematical structure of theories of resource convertibility I

    E-Print Network [OSTI]

    Tobias Fritz

    2015-04-14T23:59:59.000Z

    Resources and their use and consumption form a central part of our life. Many branches of science and engineering are concerned with the question of which given resource objects can be converted into which target resource objects. For example, information theory studies the conversion of a noisy communication channel instance into an exchange of information. Inspired by work in quantum information theory, we develop a general framework for this type of question. The convertibility of resources into other ones and the possibility of combining resources is accurately captured by the mathematics of ordered commutative monoids. As an intuitive example, we consider chemistry, where chemical reaction equations such as $\\mathrm{2H_2 + O_2} \\longrightarrow \\mathrm{2H_2O}$ are concerned both with a convertibility relation $\\longrightarrow$ and a combination operation $+$. We study ordered commutative monoids from an algebraic and functional-analytic perspective and derive a wealth of results which should have applications to concrete resource theories, such as a formula for rates of conversion. As a running example showing that ordered commutative monoids are also of purely mathematical interest, we exemplify our results with the ordered commutative monoid of graphs. While closely related to both Girard's linear logic and Deutsch's constructor theory, our framework also produces results very reminiscent of the utility theorem of von Neumann and Morgenstern in decision theory and of a theorem of Lieb and Yngvason on thermodynamics. Concerning pure algebra, our observation is that some pieces of algebra can be developed in a context in which equality is not necessarily symmetric, i.e. in which the equality relation is replaced by an ordering relation. For example, notions like cancellativity or torsion-freeness are still sensible and very natural concepts in our ordered setting.

  7. Torque magnetometry study of metamagnetic transitions in single-crystal HoNi(2)B(2)C at T approximate to 1.9 K

    E-Print Network [OSTI]

    Rathnayaka, K. D. D.; Belevtsev, B. I.; Naugle, Donald G.

    2007-01-01T23:59:59.000Z

    Torque magnetometry study of metamagnetic transitions in single-crystal HoNi2B2C at T?1.9 K K. D. D. Rathnayaka,1 B. I. Belevtsev,2,* and D. G. Naugle1,? 1Department of Physics, Texas A&M University, College Station, Texas 77843-4242, USA 2B... of superconductivity and long-range magnetic order. Although the borocarbides were studied quite intensively, certain important issues remain open. We report a torque magnetometry study of metamagnetic transitions at low tem- perature #1;T#3;1.9 K#2; in a single...

  8. Design and testing of a combustion-heated nineteen-converter SAVTEC array

    SciTech Connect (OSTI)

    Nyren, T.; Fitzpatrick, G.O.; Korringa, M.; McVey, J.; Sahines, T.

    1984-08-01T23:59:59.000Z

    The SAVTEC (Self-Adjusting Versatile Thermionic Energy Converter) is a new design approach for achieving very close (<12..mu..) interelectrode spacing in a thermionic converter. Techniques were developed for fabricating an array of nineteen SAVTEC converters. The array was incorporated in an SiC protective ''hot shell'' which also served as a radiant heat source for the emitter of each converter. The completed assembly was tested with a specially constructed combustion heat source. Electric output was generated by sixteen of the nineteen converters, despite poor thermal contact in a cooling block, which resulted in high collector temperatures. Details of the array design and test results are described.

  9. Experimental investigation of a thermionic converter with developed surface electrodes

    SciTech Connect (OSTI)

    Luke, James R.; El-Genk, Mohamed S.; Adrian, John M. [Institute for Space and Nuclear Power Studies/Chemical and Nuclear Engineering Department University of New Mexico, Albuquerque, New Mexico 87131 (United States)

    1997-01-10T23:59:59.000Z

    A thermionic converter with developed planar electrode surfaces is designed and tested. One of the electrodes has concentric circular grooves cut into its surface, while the other electrode surface is smooth. The grooves are 0.5 mm deep and 0.5 mm wide, having lands that are 1.0 mm wide. The experimental setup is flexible so that either the smooth or developed surface electrode can be operated as the emitter, with the other operating as the collector. The I-V characteristics and power output are compared for the two electrode arrangements.

  10. Experimental investigation of a thermionic converter with developed surface electrodes

    SciTech Connect (OSTI)

    Luke, J.R.; El-Genk, M.S.; Adrian, J.M. [Institute for Space and Nuclear Power Studies/Chemical and Nuclear Engineering Department University of New Mexico, Albuquerque, New Mexico87131 (United States)

    1997-01-01T23:59:59.000Z

    A thermionic converter with developed planar electrode surfaces is designed and tested. One of the electrodes has concentric circular grooves cut into its surface, while the other electrode surface is smooth. The grooves are 0.5 mm deep and 0.5 mm wide, having lands that are 1.0 mm wide. The experimental setup is flexible so that either the smooth or developed surface electrode can be operated as the emitter, with the other operating as the collector. The I-V characteristics and power output are compared for the two electrode arrangements. {copyright} {ital 1997 American Institute of Physics.}

  11. Multichannel analog-digital converter in VEKTOR-CAMAC systemsystems

    SciTech Connect (OSTI)

    Borodyanskii, M.E.

    1986-09-01T23:59:59.000Z

    This paper describes a four-channel analog-digital converter (ADC) that is implemented by large-scale integrated circuits. Resdundancy of signal conversion in intermediate cycles ensures a more accurate conversion result from cycle to cycle. The ADC is fully compatible with the Vektor system and, with slight modifications, is CAMAC compatible. The conversion time of the ADC for one channel is 5 used, the output code is 14-bit binary, the maximum integral nonlinearity is not more than 0.05% of the dynamic range of + or -10V, and the size of the random access memeory is 1024 14-bit words.

  12. Close-spaced Knudsen`s mode thermionic converter

    SciTech Connect (OSTI)

    Kucherov, R.Ya.; Nikolaev, Y.V. [Research Inst. of SIA Lutch, Podolsk (Russian Federation)

    1995-12-31T23:59:59.000Z

    It is demonstrated that the Knudsen`s mode of the thermionic converter (TIC) operation can be realized in a TIC with the interelectrode spacing 15{divided_by}30 {mu} and the emitter work function 5{divided_by}5.5 eV at the emitter temperature above 1800 K and cesium vapor pressure 0.5{divided_by}1 tor. With the use of reflective coating applied to the collector, efficiency of such TIC can achieve the level in excess of 30%.

  13. Results from the Microminiature Thermionic Converter Demonstration Testing Program

    SciTech Connect (OSTI)

    King, D.B.; Luke, J.R.; Wyant, F.J.

    1998-10-05T23:59:59.000Z

    Research is in progress to develop microminiature thermionic converters (MTCS) with high energy conversion efficiencies and variable operating temperatures using semiconductor integrated circuit (IC) fabrication methods. The use of IC techniques allows the fabrication of MTCS with cathode to anode spacing of several microns or less and with anode and cathode materials that will have work fimctions ranging from 1 eV to 3 eV. The small cathode to anode spacing and variable electrode work functions should allow the conversion of heat energy to relatively large current densities (up to tens of Amps/cmz) at relatively high conversion efficiencies ( 15-25%).

  14. Light-weight DC to very high voltage DC converter

    DOE Patents [OSTI]

    Druce, Robert L. (Union City, CA); Kirbie, Hugh C. (Dublin, CA); Newton, Mark A. (Livermore, CA)

    1998-01-01T23:59:59.000Z

    A DC-DC converter capable of generating outputs of 100 KV without a transformer comprises a silicon opening switch (SOS) diode connected to allow a charging current from a capacitor to flow into an inductor. When a specified amount of charge has flowed through the SOS diode, it opens up abruptly; and the consequential collapsing field of the inductor causes a voltage and current reversal that is steered into a load capacitor by an output diode. A switch across the series combination of the capacitor, inductor, and SOS diode closes to periodically reset the SOS diode by inducing a forward-biased current.

  15. Light-weight DC to very high voltage DC converter

    DOE Patents [OSTI]

    Druce, R.L.; Kirbie, H.C.; Newton, M.A.

    1998-06-30T23:59:59.000Z

    A DC-DC converter capable of generating outputs of 100 KV without a transformer comprises a silicon opening switch (SOS) diode connected to allow a charging current from a capacitor to flow into an inductor. When a specified amount of charge has flowed through the SOS diode, it opens up abruptly; and the consequential collapsing field of the inductor causes a voltage and current reversal that is steered into a load capacitor by an output diode. A switch across the series combination of the capacitor, inductor, and SOS diode closes to periodically reset the SOS diode by inducing a forward-biased current. 1 fig.

  16. Use of a combined lining in copper production converters

    SciTech Connect (OSTI)

    Birkle, G.V.B.; Slovikovski, V.V.; Danilova, T.A.; P'yankova, V.A.; Verzilov, N.A.

    1987-01-01T23:59:59.000Z

    The authors look at materials and methods for increasing the liner life and thermal efficiency of converters used at three copper melting combines in the Soviet Union. The refractories tested are various commercial combinations of magnesite, periclase and chromite, and the properties for which they are tested include their compression strength, heat resistance, thermal expansion, and wear resistance to slag. The authors find the refractory combination least degradable by heat and wear and calculate the savings, both in cost and energy, achieved by the combines in question by the utilization of this liner material.

  17. Bi-Directional DC-DC Converter for PHEV Applications

    SciTech Connect (OSTI)

    Abas Goodarzi

    2011-01-31T23:59:59.000Z

    Plug-In Hybrid Electric Vehicles (PHEV) require high power density energy storage system (ESS) for hybrid operation and high energy density ESS for Electric Vehicle (EV) mode range. However, ESS technologies to maximize power density and energy density simultaneously are not commercially feasible. The use of bi-directional DC-DC converter allows use of multiple energy storage, and the flexible DC-link voltages can enhance the system efficiency and reduce component sizing. This will improve fuel consumption, increase the EV mode range, reduce the total weight, reduce battery initial and life cycle cost, and provide flexibility in system design.

  18. Performance testing of the Sandy Pond HVDC converter terminal

    SciTech Connect (OSTI)

    Donahue, J.A.; Fisher, D.A.; Railing, B.D.; Tatro, P.J. (New England Power Service Co., Westborough, MA (United States))

    1993-01-01T23:59:59.000Z

    Results of several performance tests for the 1,800 MW Sandy Pond HVDC converter terminal are presented and discussed. The work progressed during 1990 and 1991 and included tests for power line carrier interference, audible sound, ac and dc line faults and dc harmonic performance. The testing was conducted as part of the commissioning program for the first stage of the Quebec-New England Phase 2 multi-terminal system. In this stage, the Radisson (Quebec) and Sandy Pond (New England) terminals are operational.

  19. Optimal design of AC filter circuits in HVDC converter stations

    SciTech Connect (OSTI)

    Saied, M.M.; Khader, S.A. [Kuwait Univ. (Kuwait). Electrical and Computer Engineering Dept.

    1995-12-31T23:59:59.000Z

    This paper investigates the reactive power as well as the harmonic conditions on both the valve and the AC-network sides of a HVDC converter station. The effect of the AC filter circuits is accurately modeled. The program is then augmented by adding an optimization routine. It can identify the optimal filter configuration, yielding the minimum current distortion factor at the AC network terminals for a prespecified fundamental reactive power to be provided by the filter. Several parameter studies were also conducted to illustrate the effect of accidental or intentional deletion of one of the filter branches.

  20. Harmonic measurements from a group connected generator HVdc converter scheme

    SciTech Connect (OSTI)

    Macdonald, S.J.; Enright, W.; Arrillaga, J. [Univ. of Canterbury, Christchurch (New Zealand)] [Univ. of Canterbury, Christchurch (New Zealand); O`Brien, M.T.

    1995-10-01T23:59:59.000Z

    A recent CIGRE document published in ELECTRA has described the potential benefits of a direct connection of generators to HVdc converters. While many theoretical contributions have been made, no practical test data has become available so far. This paper reports on harmonic tests carried out at the Benmore end of the New Zealand HVdc link operating as a group connected scheme. It was found that the measured harmonic current levels were well below specified generator ratings. Dynamic simulation accurately predicted the harmonic currents whereas the results of a steady state formulation were less reliable.

  1. Thermally induced evolution of morphology on ceramic surfaces in a thermionic converter

    SciTech Connect (OSTI)

    Zavadil, K.R. [Sandia National Laboratories P.O. Box 5800 Albuquerque, New Mexico87185-0342 (United States); Olson, D.L. [Team Specialty Services 901 University Blvd. SE Albuquerque, New Mexico87106-4439 (United States); Klinkov, A.E. [JS INTERTEK 123182Moscow Kurchatov Sq. 1 (Russian Federation)

    1997-01-01T23:59:59.000Z

    The morphology of alumina and scandia ceramics exposed to controlled vacuum and diffusion modes in a thermionic converter has been studied. Evidence for vaporization at a temperature of 1770 K is manifest in the resulting surface morphologies of both ceramics, consistent with reported sample mass loss. Alumina shows intergranular relief with the formation of terrace-step structure on the grain surfaces. Terrace formation is not directly observed on scandia, however the development of vertical structure and maintenance of voids indicates that vaporization is initiated by structure at the grain edges. Extensive Sc{sub 2}O{sub 3} re-deposition occurs on the scandia surface, possibly mediated by the presence of molybdenum and tungsten. Evidence exists for refractory metal secondary phase formation in this deposit in the form of Sc{sub 6}MO{sub 12} (M=W or Mo). Alumina also shows evidence for materials{close_quote} interactions in the form of tantalum assisted vaporization which significantly alters the terrace structure. {copyright} {ital 1997 American Institute of Physics.}

  2. Thermally induced evolution of morphology on ceramic surfaces in a thermionic converter

    SciTech Connect (OSTI)

    Zavadil, Kevin R.; Olson, David L.; Klinkov, Alexander E. [Sandia National Laboratories P.O. Box 5800 Albuquerque, New Mexico 87185-0342 (United States); Team Specialty Services 901 University Blvd. SE Albuquerque, New Mexico 87106-4439 (United States); JS INTERTEK 123182 Moscow Kurchatov Sq. 1 (Russian Federation)

    1997-01-10T23:59:59.000Z

    The morphology of alumina and scandia ceramics exposed to controlled vacuum and diffusion modes in a thermionic converter has been studied. Evidence for vaporization at a temperature of 1770 K is manifest in the resulting surface morphologies of both ceramics, consistent with reported sample mass loss. Alumina shows intergranular relief with the formation of terrace-step structure on the grain surfaces. Terrace formation is not directly observed on scandia, however the development of vertical structure and maintenance of voids indicates that vaporization is initiated by structure at the grain edges. Extensive Sc{sub 2}O{sub 3} re-deposition occurs on the scandia surface, possibly mediated by the presence of molybdenum and tungsten. Evidence exists for refractory metal secondary phase formation in this deposit in the form of Sc{sub 6}MO{sub 12} (M=W or Mo). Alumina also shows evidence for materials' interactions in the form of tantalum assisted vaporization which significantly alters the terrace structure.

  3. Thermally induced evolution of morphology on ceramic surfaces in a thermionic converter

    SciTech Connect (OSTI)

    Zavadil, K.R. [Sandia National Labs., Albuquerque, NM (United States); Olson, D.L. [Team Specialty Services, Albuquerque, NM (United States); Klinkov, A.E. [JS Intertek, Kurchatov (Russian Federation)

    1996-12-01T23:59:59.000Z

    The morphology of alumina and scandia ceramics exposed to controlled vacuum and diffusion modes in a thermionic converter has been studied. Evidence for vaporization at a temperature of 1,770 K is manifest in the resulting surface morphologies of both ceramics, consistent with reported sample mass loss. Alumina shows intergranular relief with the formation of terrace--step structure on the grain surfaces. Terrace formation is not directly observed on scandia, however the development of vertical structure and maintenance of voids indicates that vaporization is initiated by structure at the grain edges. Extensive Sc{sub 2}O{sub 3} re-deposition occurs on the scandia surface, possibly mediated by the presence of molybdenum and tungsten. Evidence exists for refractory metal secondary phase formation in this deposit in the form of Sc{sub 6}MO{sub 12} (M = W or Mo). Alumina also shows evidence for materials` interactions in the form of tantalum assisted vaporization which significantly alters the terrace structure.

  4. Development of a Novel Bi-Directional Isolated Multiple-Input DC-DC Converter

    SciTech Connect (OSTI)

    Li, H.

    2005-10-24T23:59:59.000Z

    There is vital need for a compact, lightweight, and efficient energy-storage system that is both affordable and has an acceptable cycle life for the large-scale production of electric vehicles (EVs) and hybrid electric vehicles (HEVs). Most of the current research employs a battery-storage unit (BU) combined with a fuel cell (FC) stack in order to achieve the operating voltage-current point of maximum efficiency for the FC system. A system block diagram is shown in Fig.1.1. In such a conventional arrangement, the battery is sized to deliver the difference between the energy required by the traction drive and the energy supplied by the FC system. Energy requirements can increase depending on the drive cycle over which the vehicle is expected to operate. Peak-power transients result in an increase of losses and elevated temperatures which result in a decrease in the lifetime of the battery. This research will propose a novel two-input direct current (dc) dc to dc converter to interface an additional energy-storage element, an ultracapacitor (UC), which is shown in Fig.1.2. It will assist the battery during transients to reduce the peak-power requirements of the battery.

  5. New generation polyphase resonant converter-modulators for the Korean atomic energy research institute

    SciTech Connect (OSTI)

    Reass, William A [Los Alamos National Laboratory; Baca, David M [Los Alamos National Laboratory; Gribble, Robert F [Los Alamos National Laboratory

    2009-01-01T23:59:59.000Z

    This paper will present operational data and performance parameters of the newest generation polyphase resonant high voltage converter modulator (HVCM) as developed and delivered to the KAERI 100 MeV ''PEFP'' accelerator [1]. The KAERI design realizes improvements from the SNS and SLAC designs [2]. To improve the IGBT switching performance at 20 kHz for the KAERI system, the HVCM utilizes the typical zero-voltage-switching (ZVS) at turn on and as well as artificial zero-current-switching (ZCS) at turn-off. The new technique of artificial ZCS technique should result in a 6 fold reduction of IGBT switching losses (3). This improves the HCVM conversion efficiency to better than 95% at full average power, which is 500 kW for the KAERI two klystron 105 kV, 50 A application. The artificial ZCS is accomplished by placing a resonant RLC circuit across the input busswork to the resonant boost transformer. This secondary resonant circuit provides a damped ''kick-back'' to assist in IGBT commutation. As the transformer input busswork is extremely low inductance (< 10 nH), the single RLC network acts like it is across each of the four IGBT collector-emitter terminals of the H-bridge switching network. We will review these topological improvements and the overall system as delivered to the KAERI accelerator and provide details of the operational results.

  6. TEC as electric generator in an automobile catalytic converter

    SciTech Connect (OSTI)

    Svensson, R. [Chalmers Univ. of Technology, Goeteborg (Sweden); Holmlid, L. [Univ. of Goeteborg (Sweden). Dept. of Physical Chemistry

    1996-12-31T23:59:59.000Z

    Modern cars use more and more electric power due to more on-board electric systems, e.g., ABS brakes, active suspension systems, electric windows, chair adjustment systems and electronic engine control systems. One possible energy source for electricity generation is to use the waste heat from the car`s engine, which generally is as much as 80% of the total energy from the combustion of the gasoline. Maybe the best location to tap the excess heat is the Catalytic Converter (Cat) in the exhaust system or perhaps at the exhaust pipes close to the engine. The Cat must be kept within a certain temperature interval. Large amounts of heat are dissipated through the wall of the Cat. A Thermionic Energy Converter (TEC) in coaxial form could conveniently be located around the ceramic cartridge of the Cat. Since the TEC is a rather good heat insulator before it reaches its working temperature the Cat will reach working temperature faster, and the final temperature of it can be controlled better when encapsulated in a concentric TEC arrangement. It is also possible to regulate the temperature of the Cat and the TEC by controlling the electrical load of the TEC. The possible working temperatures of present and future Cats appear very suitable for the new low work function collector TEC, which has been demonstrated to work down to 470 K.

  7. Thermionic converters for an Integrated Solar Upper Stage (ISUS)

    SciTech Connect (OSTI)

    Anderson, W.G.; Horner-Richardson, K. [Thermacore, Inc., Lancaster, PA (United States)

    1996-12-31T23:59:59.000Z

    The Integrated Solar Upper Stage (ISUS) is a solar bimodal system which combines thermal propulsion and electric power generation in a single integrated system. A thermionic converter was designed and fabricated for the ISUS system. The ISUS thermionic energy converters differ from previous designs, due to the significant changes in operating temperature prior to and during an eclipse, with the emitter temperature increasing from 1,900 K to 2,200 K, and then back again. A complete thermal and electrical model was developed for a planar diode to determine optimum operating dimensions and parameters. The model includes an overall energy balance for the diode, and changes the interelectrode gap spacing due to thermal expansion of the parts as the emitter and/or collector temperatures change. Cesium pressure can be chosen from an external liquid reservoir, an integral reservoir using cesium intercalated into graphite attached to the collector heat pipe, or optimum cesium pressure. With optimum cesium pressure, the maximum efficiency increases from 14% to 16% as the emitter temperature increases from 1,900 K to 2,200 K. The improvement in efficiency is only 2% as the emitter temperature is increased. Optimum efficiency requires an external, actively controlled liquid reservoir.

  8. Triple voltage dc-to-dc converter and method

    DOE Patents [OSTI]

    Su, Gui-Jia (Knoxville, TN)

    2008-08-05T23:59:59.000Z

    A circuit and method of providing three dc voltage buses and transforming power between a low voltage dc converter and a high voltage dc converter, by coupling a primary dc power circuit and a secondary dc power circuit through an isolation transformer; providing the gating signals to power semiconductor switches in the primary and secondary circuits to control power flow between the primary and secondary circuits and by controlling a phase shift between the primary voltage and the secondary voltage. The primary dc power circuit and the secondary dc power circuit each further comprising at least two tank capacitances arranged in series as a tank leg, at least two resonant switching devices arranged in series with each other and arranged in parallel with the tank leg, and at least one voltage source arranged in parallel with the tank leg and the resonant switching devices, said resonant switching devices including power semiconductor switches that are operated by gating signals. Additional embodiments having a center-tapped battery on the low voltage side and a plurality of modules on both the low voltage side and the high voltage side are also disclosed for the purpose of reducing ripple current and for reducing the size of the components.

  9. Converting Maturing Nuclear Sites to Integrated Power Production Islands

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Solbrig, Charles W.

    2011-01-01T23:59:59.000Z

    Nuclear islands, which are integrated power production sites, could effectively sequester and safeguard the US stockpile of plutonium. A nuclear island, an evolution of the integral fast reactor, utilizes all the Transuranics (Pu plus minor actinides) produced in power production, and it eliminates all spent fuel shipments to and from the site. This latter attribute requires that fuel reprocessing occur on each site and that fast reactors be built on-site to utilize the TRU. All commercial spent fuel shipments could be eliminated by converting all LWR nuclear power sites to nuclear islands. Existing LWR sites have the added advantage ofmorealready possessing a license to produce nuclear power. Each could contribute to an increase in the nuclear power production by adding one or more fast reactors. Both the TRU and the depleted uranium obtained in reprocessing would be used on-site for fast fuel manufacture. Only fission products would be shipped to a repository for storage. The nuclear island concept could be used to alleviate the strain of LWR plant sites currently approaching or exceeding their spent fuel pool storage capacity. Fast reactor breeding ratio could be designed to convert existing sites to all fast reactors, or keep the majority thermal.less

  10. EMISSIONS REDUCTIONS USING HYDROGEN FROM PLASMATRON FUEL CONVERTERS

    SciTech Connect (OSTI)

    Bromberg, L

    2000-08-20T23:59:59.000Z

    Substantial progress in engine emission control is needed in order to meet present and proposed regulations for both spark ignition and diesel engines. Tightening regulations throughout the world reflect the ongoing concern with vehicle emissions. Recently developed compact plasmatron fuel converters have features that are suitable for onboard production of hydrogen for both fuel pretreatment and for exhaust aftertreatment applications. Systems that make use of these devices in conjunction with aftertreatment catalysts have the potential to improve significantly prospects for reduction of diesel engine emissions. Plasmatron fuel converters can provide a rapid response compact means to transform efficiently a wide range of hydrocarbon fuels into hydrogen rich gas. They have been used to reform natural gas [Bromberg1], gasoline [Green], diesel [Bromberg2] and hard-to-reform biofuels [Cohn1] into hydrogen rich gas (H2 + CO). The development of these devices has been pursued for the purpose of reducing engine exhaust pollutants by providing hydrogen rich gas for combustion in spark ignition and possibly diesel engines, as shown in Figure 1 [Cohn2]. Recent developments in compact plasmatron reformer design at MIT have resulted in substantial decreases in electrical power requirements. These new developments also increase the lifetime of the electrodes.

  11. Loss mechanisms in turbine tip clearance flows

    E-Print Network [OSTI]

    Huang, Arthur (Arthur C.)

    2011-01-01T23:59:59.000Z

    Numerical simulations of tip clearance ow have been carried out to dene the loss generation mechanisms associated with tip leakage in unshrouded axial turbines. Mix- ing loss between the leakage, which takes the form of a ...

  12. Loss of coordination in competitive supply chains

    E-Print Network [OSTI]

    Teo, Koon Soon

    2009-01-01T23:59:59.000Z

    The loss of coordination in supply chains quantifies the inefficiency (i.e. the loss of total profit) due to the presence of competition in the supply chain. In this thesis, we discuss four models: one model with multiple ...

  13. Effects of emitter sheath ion reflection and trapped ions on thermionic converter performance using an isothermal electron model

    SciTech Connect (OSTI)

    Main, G.L.; Lam, S.H.

    1987-06-01T23:59:59.000Z

    This paper couples exact collisionless sheath calculations to an isothermal electron model of a thermionic converter. The emitter sheath structure takes into account reflected ions, trapped ions, and surface emission ions. It is shown that lessening the net loss of ions at the emitter in the ignited mode by these phenomena degrades performance. In addition, it is shown that when the emitter returns too many of the ions, the arc is extinguished because there is insufficient resistive heating to maintain the necessary plasma electron temperature for ionization. These results suggest that the ignited mode cannot be improved much. However, nonignited modes in which the electron temperature remains low, such as the pulsed mode, do not suffer from this adverse behavior.

  14. 7, 1009710129, 2007 Chemical ozone loss

    E-Print Network [OSTI]

    ACPD 7, 1009710129, 2007 Chemical ozone loss in the Arctic winter 19911992 S. Tilmes et al. Title Chemistry and Physics Discussions Chemical ozone loss in the Arctic winter 19911992 S. Tilmes 1 , R. M Chemical ozone loss in the Arctic winter 19911992 S. Tilmes et al. Title Page Abstract Introduction

  15. 4, 21672238, 2004 Ozone loss and

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    ACPD 4, 21672238, 2004 Ozone loss and chlorine activation in the Arctic winters 19912003 S Union 2004 Atmospheric Chemistry and Physics Discussions Ozone loss and chlorine activation Correspondence to: S. Tilmes (simone.tilmes@t-online.de) 2167 #12;ACPD 4, 21672238, 2004 Ozone loss and chlorine

  16. Technical report Minimizing Calibrated Loss using

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    Technical report Minimizing Calibrated Loss using Stochastic Low-Rank Newton Descent for large algorithm (SGD) for the minimization of classical Hinge Loss in the primal space. Although com- plexity- imization of any calibrated loss in the primal space. SLND approximates the inverse Hessian by the best low

  17. 1154 IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, VOL. 49, NO. 5, OCTOBER 2002 A High-Torque Low-Speed Multiphase Brushless

    E-Print Network [OSTI]

    Simes, Marcelo Godoy

    -Speed Multiphase Brushless Machine--A Perspective Application for Electric Vehicles Marcelo Godoy Simes, Senior, analysis, simulation, and modeling of a high-torque low-speed multiphase permanent- magnet brushless-driven wheel motor drive system comprising a multiphase multipole topology controller. It presents the high

  18. Efficient, High-Torque Electric Vehicle Motor: Advanced Electric Vehicle Motors with Low or No Rare Earth Content

    SciTech Connect (OSTI)

    None

    2012-01-01T23:59:59.000Z

    REACT Project: QM Power will develop a new type of electric motor with the potential to efficiently power future generations of EVs without the use of rare-earth-based magnets. Many of todays EV motors use rare earth magnets to efficiently provide torque to the wheels. QM Powers motors would contain magnets that use no rare earth minerals, are light and compact, and can deliver more power with greater efficiency and at reduced cost. Key innovations in this project include a new motor design with iron-based magnetic materials, a new motor control technique, and advanced manufacturing techniques that substantially reduce the cost of the motor. The ultimate goal of this project is to create a cost-effective EV motor that offers the rough peak equivalent of 270 horsepower.

  19. QCD Collisional Energy Loss Reexamined

    SciTech Connect (OSTI)

    Peshier, A. [Institut fuer Theoretische Physik, Universitaet Giessen, 35392 Giessen (Germany)

    2006-11-24T23:59:59.000Z

    It is shown that at a large temperature and E{yields}{infinity} the QCD collisional energy loss reads dE/dx{approx}{alpha}(m{sub D}{sup 2})T{sup 2}. Compared to previous approaches, which led to dE{sup B}/dx{approx}{alpha}{sup 2}T{sup 2}ln(ET/m{sub D}{sup 2}) similar to the Bethe-Bloch formula in QED, we take into account the running of the strong coupling. As one significant consequence, due to asymptotic freedom, dE/dx becomes E independent for large parton energies. Some implications with regard to heavy ion collisions are pointed out.

  20. Spring structure for a thermionic converter emitter support arrangement

    SciTech Connect (OSTI)

    Allen, Daniel T. (La Jolla, CA)

    1992-01-01T23:59:59.000Z

    A support is provided for use in a thermionic converter to support an end of an emitter to keep it out of contact with a surrounding collector while allowing the emitter end to move axially as its temperature changes. The emitter end (34) is supported by a spring structure (44) that includes a pair of Belleville springs, and the spring structure is supported by a support structure (42) fixed to the housing that includes the collector. The support structure is in the form of a sandwich with a small metal spring-engaging element (74) at the front end, a larger metal main support (76) at the rear end that is attached to the housing, and with a ceramic layer (80) between them that is bonded by hot isostatic pressing to the metal element and metal main support. The spring structure can include a loose wafer (120) captured between the Belleville springs.

  1. Spring structure for a thermionic converter emitter support arrangement

    DOE Patents [OSTI]

    Allen, D.T.

    1992-03-17T23:59:59.000Z

    A support is provided for use in a thermionic converter to support an end of an emitter to keep it out of contact with a surrounding collector while allowing the emitter end to move axially as its temperature changes. The emitter end is supported by a spring structure that includes a pair of Belleville springs, and the spring structure is supported by a support structure fixed to the housing that includes the collector. The support structure is in the form of a sandwich with a small metal spring-engaging element at the front end, a larger metal main support at the rear end that is attached to the housing, and with a ceramic layer between them that is bonded by hot isostatic pressing to the metal element and metal main support. The spring structure can include a loose wafer captured between the Belleville springs. 7 figs.

  2. Results from the microminiature thermionic converter demonstration testing program

    SciTech Connect (OSTI)

    King, Donald B.; Wyant, Francis J. [International Nuclear Safety Department, Sandia National Laboratories, MS-0744, Albuquerque, New Mexico 87185 (United States)] Luke, James R. [New Mexico Engineering Research Institute, 901 University Blvd. SE, Albuquerque, New Mexico 87106 (United States)

    1999-01-01T23:59:59.000Z

    Research is in progress to develop microminiature thermionic converters (MTCs) with high energy conversion efficiencies and variable operating temperatures using semiconductor integrated circuit (IC) fabrication methods. The use of IC techniques allows the fabrication of MTCs with cathode to anode spacing of several microns or less and with anode and cathode materials that will have work functions ranging from 1 eV to 3 eV. The small cathode to anode spacing and variable electrode work functions should allow the conversion of heat energy to relatively large current densities (up to tens of Amps/cm{sup 2}) at relatively high conversion efficiencies (15{endash}25{percent}). {copyright} {ital 1999 American Institute of Physics.}

  3. The Force of a Tsunami on a Wave Energy Converter

    E-Print Network [OSTI]

    O'Brien, Laura; Renzi, Emiliano; Dutykh, Denys; Dias, Frdric

    2012-01-01T23:59:59.000Z

    With an increasing emphasis on renewable energy resources, wave power technology is fast becoming a realistic solution. However, the recent tsunami in Japan was a harsh reminder of the ferocity of the ocean. It is known that tsunamis are nearly undetectable in the open ocean but as the wave approaches the shore its energy is compressed creating large destructive waves. The question posed here is whether a nearshore wave energy converter (WEC) could withstand the force of an incoming tsunami. The analytical 3D model of Renzi & Dias (2012) developed within the framework of a linear theory and applied to an array of fixed plates is used. The time derivative of the velocity potential allows the hydrodynamic force to be calculated.

  4. NREL Research on Converting Biomass to Liquid Fuels

    ScienceCinema (OSTI)

    None

    2013-05-29T23:59:59.000Z

    Unlike other renewable energy sources, biomass can be converted directly into liquid fuels, called "biofuels," to help meet transportation fuel needs. The two most common types of biofuels are ethanol and biodiesel. Today, ethanol is made from starches and sugars, but at the National Renewable Energy Laboratory (NREL) scientists are developing technology to allow it to be made from cellulose and hemicellulose, the fibrous material that makes up the bulk of most plant matter. Biodiesel is made by combining alcohol (usually methanol) with vegetable oil, animal fat, or recycled cooking grease. It can be used as an additive (typically 20%) to reduce vehicle emissions or in its pure form as a renewable alternative fuel for diesel engines. For a text version of this video visit http://www.nrel.gov/learning/re_biofuels.html

  5. NREL Research on Converting Biomass to Liquid Fuels

    SciTech Connect (OSTI)

    None

    2010-01-01T23:59:59.000Z

    Unlike other renewable energy sources, biomass can be converted directly into liquid fuels, called "biofuels," to help meet transportation fuel needs. The two most common types of biofuels are ethanol and biodiesel. Today, ethanol is made from starches and sugars, but at the National Renewable Energy Laboratory (NREL) scientists are developing technology to allow it to be made from cellulose and hemicellulose, the fibrous material that makes up the bulk of most plant matter. Biodiesel is made by combining alcohol (usually methanol) with vegetable oil, animal fat, or recycled cooking grease. It can be used as an additive (typically 20%) to reduce vehicle emissions or in its pure form as a renewable alternative fuel for diesel engines. For a text version of this video visit http://www.nrel.gov/learning/re_biofuels.html

  6. A Study of Radiative Bottomonium Transitions using Converted Photons

    SciTech Connect (OSTI)

    Lees, J.P.; Poireau, V.; Prencipe, E.; Tisserand, V.; /Annecy, LAPP; Garra Tico, J.; Grauges, E.; /Barcelona U., ECM; Martinelli, M.; /INFN, Bari /Bari U.; Milanes, D.A.; /INFN, Bari; Palano, A.; Pappagallo, M.; /INFN, Bari /Bari U.; Eigen, G.; Stugu, B.; Sun, L.; /Bergen U.; Brown, D.N.; Kerth, L.T.; Kolomensky, Yu.G.; Lynch, G.; /UC, Berkeley; Koch, H.; Schroeder, T.; /Ruhr U., Bochum; Asgeirsson, D.J.; Hearty, C.; /British Columbia U. /Brunel U. /Novosibirsk, IYF /UC, Irvine /UC, Riverside /UC, Santa Barbara /UC, Santa Cruz /Caltech /Cincinnati U. /Colorado U. /Colorado State U. /Dortmund U. /Dresden, Tech. U. /Ecole Polytechnique /Edinburgh U. /INFN, Ferrara /INFN, Ferrara /Ferrara U. /INFN, Ferrara /Frascati /INFN, Genoa /Genoa U. /INFN, Genoa /INFN, Genoa /Genoa U. /INFN, Genoa /Indian Inst. Tech., Guwahati /Harvard U. /Harvey Mudd Coll. /Heidelberg U. /Humboldt U., Berlin /Imperial Coll., London /Iowa State U. /Iowa State U. /Johns Hopkins U. /Paris U., VI-VII /LLNL, Livermore /Liverpool U. /Queen Mary, U. of London /Royal Holloway, U. of London /Royal Holloway, U. of London /Louisville U. /Mainz U., Inst. Kernphys. /Manchester U. /Maryland U. /Massachusetts U., Amherst /MIT /McGill U. /INFN, Milan /Milan U. /INFN, Milan /INFN, Milan /Milan U. /Mississippi U. /Montreal U. /INFN, Naples /Naples U. /NIKHEF, Amsterdam /NIKHEF, Amsterdam /Notre Dame U. /Ohio State U. /Oregon U. /INFN, Padua /Padua U. /INFN, Padua /INFN, Padua /Padua U. /Paris U., VI-VII /INFN, Perugia /Perugia U. /INFN, Pisa /Pisa U. /INFN, Pisa /Pisa, Scuola Normale Superiore /INFN, Pisa /Pisa U. /INFN, Pisa /INFN, Pisa /Pisa U. /INFN, Pisa /Princeton U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /Rostock U. /Rutherford /DAPNIA, Saclay /SLAC /South Carolina U. /Southern Methodist U. /Stanford U., Phys. Dept. /SUNY, Albany /Tel Aviv U. /Tennessee U. /Texas Nuclear Corp., Austin /Texas U., Dallas /INFN, Turin /Turin U. /INFN, Trieste /Trieste U. /Valencia U. /Victoria U. /Warwick U. /Wisconsin U., Madison

    2011-08-15T23:59:59.000Z

    The authors use (111 {+-} 1) million {Upsilon}(3S) and (89 {+-} 1) million {Upsilon}(2S) events recorded by the BABAR detector at the PEP-II B-factory at SLAC to perform a study of radiative transitions betwen bottomonium states using photons that have been converted to e{sup +}e{sup -} pairs by the detector material. They observe {Upsilon}(3S) {yields} {gamma}{chi}{sub b0,2}(1P) decay, make precise measurements of the branching fractions for {chi}{sub b1,2}(1P, 2P) {yields} {gamma}{Upsilon}(1S) and {chi}{sub b1,2}(2P) {yields} {gamma}{Upsilon}(2S) decays, and search for radiative decay to the {eta}{sub b}(1S) and {eta}{sub b}(2S) states.

  7. Apparatuses and method for converting electromagnetic radiation to direct current

    DOE Patents [OSTI]

    Kotter, Dale K; Novack, Steven D

    2014-09-30T23:59:59.000Z

    An energy conversion device may include a first antenna and a second antenna configured to generate an AC current responsive to incident radiation, at least one stripline, and a rectifier coupled with the at least one stripline along a length of the at least one stripline. An energy conversion device may also include an array of nanoantennas configured to generate an AC current in response to receiving incident radiation. Each nanoantenna of the array includes a pair of resonant elements, and a shared rectifier operably coupled to the pair of resonant elements, the shared rectifier configured to convert the AC current to a DC current. The energy conversion device may further include a bus structure operably coupled with the array of nanoantennas and configured to receive the DC current from the array of nanoantennas and transmit the DC current away from the array of nanoantennas.

  8. Reference Model 5 (RM5): Oscillating Surge Wave Energy Converter

    SciTech Connect (OSTI)

    Yu, Y. H.; Jenne, D. S.; Thresher, R.; Copping, A.; Geerlofs, S.; Hanna, L. A.

    2015-01-01T23:59:59.000Z

    This report is an addendum to SAND2013-9040: Methodology for Design and Economic Analysis of Marine Energy Conversion (MEC) Technologies. This report describes an Oscillating Water Column Wave Energy Converter (OSWEC) reference model design in a complementary manner to Reference Models 1-4 contained in the above report. A conceptual design for a taut moored oscillating surge wave energy converter was developed. The design had an annual electrical power of 108 kilowatts (kW), rated power of 360 kW, and intended deployment at water depths between 50 m and 100 m. The study includes structural analysis, power output estimation, a hydraulic power conversion chain system, and mooring designs. The results were used to estimate device capital cost and annual operation and maintenance costs. The device performance and costs were used for the economic analysis, following the methodology presented in SAND2013-9040 that included costs for designing, manufacturing, deploying, and operating commercial-scale MEC arrays up to 100 devices. The levelized cost of energy estimated for the Reference Model 5 OSWEC, presented in this report, was for a single device and arrays of 10, 50, and 100 units, and it enabled the economic analysis to account for cost reductions associated with economies of scale. The baseline commercial levelized cost of energy estimate for the Reference Model 5 device in an array comprised of 10 units is $1.44/kilowatt-hour (kWh), and the value drops to approximately $0.69/kWh for an array of 100 units.

  9. Reference Model 6 (RM6): Oscillating Wave Energy Converter.

    SciTech Connect (OSTI)

    Bull, Diana L; Smith, Chris; Jenne, Dale Scott; Jacob, Paul; Copping, Andrea; Willits, Steve; Fontaine, Arnold; Brefort, Dorian; Gordon, Margaret Ellen; Copeland, Robert; Jepsen, Richard A.

    2014-10-01T23:59:59.000Z

    This report is an addendum to SAND2013-9040: Methodology for Design and Economic Analysis of Marine Energy Conversion (MEC) Technologies. This report describes an Oscillating Water Column Wave Energy Converter reference model design in a complementary manner to Reference Models 1-4 contained in the above report. In this report, a conceptual design for an Oscillating Water Column Wave Energy Converter (WEC) device appropriate for the modeled reference resource site was identified, and a detailed backward bent duct buoy (BBDB) device design was developed using a combination of numerical modeling tools and scaled physical models. Our team used the methodology in SAND2013-9040 for the economic analysis that included costs for designing, manufacturing, deploying, and operating commercial-scale MEC arrays, up to 100 devices. The methodology was applied to identify key cost drivers and to estimate levelized cost of energy (LCOE) for this RM6 Oscillating Water Column device in dollars per kilowatt-hour (%24/kWh). Although many costs were difficult to estimate at this time due to the lack of operational experience, the main contribution of this work was to disseminate a detailed set of methodologies and models that allow for an initial cost analysis of this emerging technology. This project is sponsored by the U.S. Department of Energy's (DOE) Wind and Water Power Technologies Program Office (WWPTO), within the Office of Energy Efficiency & Renewable Energy (EERE). Sandia National Laboratories, the lead in this effort, collaborated with partners from National Laboratories, industry, and universities to design and test this reference model.

  10. Genomic Responses to the Loss of LRPPRC MITOCHONDRIAL AND NUCLEAR GENOMIC RESPONSES TO LOSS OF LRPPRC

    E-Print Network [OSTI]

    Mootha, Vamsi K.

    of Systems Biology, Harvard Medical School, Boston, MA 02446 USA Running head: Genomic Responses to the LossGenomic Responses to the Loss of LRPPRC 1 MITOCHONDRIAL AND NUCLEAR GENOMIC RESPONSES TO LOSS with the loss of LRPPRC. Using this strategy, we discovered a specific role for LRPPRC in the expression of all

  11. Solar energy power generators with advanced thermionic converters for spacecraft applications

    SciTech Connect (OSTI)

    Sahin, S.

    1981-01-01T23:59:59.000Z

    This study presents (1) a 50 kW/sub e/ solar energy generator in a geostationary orbit for direct tv-broadcasting and (2) a 10 GW/sub e/ space power plant, with the basic engineering outlines using an advanced thermionic converter proposal given for each. Further, a comparison of the main technical data for the generators with corresponding energy output using (1) advanced thermionic converter and (2) ordinary thermionic converter without auxiliary emitter is shown. 25 refs.

  12. Soft-Switching High-Frequency AC-Link Universal Power Converters with Galvanic Isolation

    E-Print Network [OSTI]

    Amirabadi, Mahshid

    2013-08-07T23:59:59.000Z

    ) direct drive using wound-field synchronous generator [10]. ...................................................................................................... 6 Figure 6 Dc-dc buck-boost converter: (a) configuration, (b) energizing mode (mode 1), (c...) de-energizing mode (mode 2), (d) voltage and current waveforms ........ 12 Figure 7 An alternative representation of the dc-dc buck-boost converter ...................... 13 Figure 8 Dc-dc ac-link buck-boost converter: configuration, behavior...

  13. An Integrated Onboard Charger and Accessary Power Converter for Plug-in Electric Vehicles

    SciTech Connect (OSTI)

    Su, Gui-Jia [ORNL; Tang, Lixin [ORNL

    2013-01-01T23:59:59.000Z

    Abstract: In this paper, an integrated onboard battery charger and accessary dc-dc converter for plug-in electric vehicles (PEVs) is presented. The idea is to utilize the already available traction drive inverters and motors of a PEV as the frond converter of the charger circuit and the transformer of the 14 V accessary dc-dc converter to provide galvanic isolation. The topology was verified by modeling and experimental results on a 5 kW charger prototype

  14. Repetitive and Iterative Learning Control for Power Converter and Precision Motion Control

    E-Print Network [OSTI]

    Teng, Kuo-Tai

    2014-01-01T23:59:59.000Z

    3 Repetitive Control of Power Inverter for Harmonic4 Repetitive Control of Power Rectifier for HarmonicThe typical PI controlled power converters can not guarantee

  15. New Family of Multilevel Matrix Converters for Wind Power Applications: Final Report, July 2002 - March 2006

    SciTech Connect (OSTI)

    Erickson, R.; Angkititrakul, S.; Almazeedi, K.

    2006-12-01T23:59:59.000Z

    The goal of this project was to develop a new modular multilevel matrix converter for wind power applications and to demonstrate a working scale model in the laboratory.

  16. Coal-fired furnace for testing of thermionic converters. Topical report

    SciTech Connect (OSTI)

    Not Available

    1980-10-01T23:59:59.000Z

    The development of thermionic converter technology has progressed to make near-term applications interesting. One of these applications is the thermionic topping of a pulverized coal-fired central station powerplant. Up to now, thermionic converters have been flame tested using natural gas as fuel. A new test furnace is required for evaluation of thermionic converters in a coal-fired environment. The design and costs of a facility which adapts a coal-fired furnace built by Foster Wheeler Development Corporation (FWDC) for thermionic converter testing are discussed. Such a facility would be exempt from air pollution regulations because of its low firing rate.

  17. angiotensin-converting enzyme levels: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    enzyme activity is significantly determined by a gene polymorphism. Homozygous Brown Norway rats have higher plasma angiotensin I-converting enzyme (more) Jalil Milad, Jorge...

  18. A High Power Density DC-DC Converter for Distributed PV Architectures

    SciTech Connect (OSTI)

    Mohammed S. Agamy; Song Chi; Ahmed Elasser; Maja Harfman-Todorovic; Yan Jiang; Frank Mueller; Fengfeng Tao

    2012-06-01T23:59:59.000Z

    In order to maximize solar energy harvesting capabilities, power converters have to be designed for high efficiency and good MPPT and voltage/current performance. When many converters are used in distributed systems, power density also becomes an important factor as it allows for simpler system integration. In this paper a high power density string dc-dc converter suitable for distributed medium to large scale PV installation is presented. A simple partial power processing topology, implemented with all silicon carbide devices provides high efficiency as well as high power density. A 3.5kW, 100kHz converter is designed and tested to verify the proposed methods.

  19. ac-dc back-to-back converter: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    and simulation of the interconnection of a back-to-back converter modulated transformers (MTF in the bond graph language) instead of the pairs of complementary switches...

  20. DC-DC Converter Topology Assessment for Large Scale Distributed Photovoltaic Plant Architectures

    SciTech Connect (OSTI)

    Mohammed S. Agamy; Maja Harfman-Todorovic; Ahmed Elasser; Juan A. Sabate; Robert L. Steigerwald; Yan Jiang; Somasundaram Essakiappan

    2011-07-01T23:59:59.000Z

    Distributed photovoltaic (PV) plant architectures are emerging as a replacement for the classical central inverter based systems. However, power converters of smaller ratings may have a negative impact on system efficiency, reliability and cost. Therefore, it is necessary to design converters with very high efficiency and simpler topologies in order not to offset the benefits gained by using distributed PV systems. In this paper an evaluation of the selection criteria for dc-dc converters for distributed PV systems is performed; this evaluation includes efficiency, simplicity of design, reliability and cost. Based on this evaluation, recommendations can be made as to which class of converters is best fit for this application.

  1. Application of direct pulsewidth modulation scheme to AC-DC converters: - a way to reduce ripple

    E-Print Network [OSTI]

    Zhang, Yuemin

    1993-01-01T23:59:59.000Z

    Modulation (ISPWM), 4 Direct Pulsewidth Modulation (DPWM). 15 5 Single Phase Half Controlled PWM ac-dc Converter . 6 Single Phase Full controlled PWM ac-dc Converter . 18 18 7 Simulation of SPWM ac-dc Converter. 20 8 Output Voltage Spectra of SPWM ac... 30 Balanced Three Phase Inputs 31 Output Voltage of A Three Phase Full Controlled ac-dc SPWM Converter. 42 32 Output Voltage of A Three Phase Full Controlled ac-dc EPWM Con- verter 33 Output Voltage of A Three Phase Full Controlled ac-dc ISPWM Con...

  2. Bibliography on overvoltage protection and insulation coordination of HVDC converter stations, 1979-1989

    SciTech Connect (OSTI)

    Not Available

    1991-04-01T23:59:59.000Z

    This bibliography is a listing of references on the subject of overvoltage protection and insulation coordination of HVDC converter stations, for the years 1979 through 1989.

  3. Multilayer Platform for Ultra-Low-Loss Waveguide Applications

    E-Print Network [OSTI]

    2012-01-01T23:59:59.000Z

    1, 2012 Multilayer Platform for Ultra-Low-Loss Waveguidepreviously demonstrated ultra-low-loss technologies. Groupet al. : MULTILAYER PLATFORM FOR ULTRA-LOW-LOSS WAVEGUIDE

  4. Effect of plasmonic losses on light emission enhancement in quantum-wells coupled to metallic gratings

    SciTech Connect (OSTI)

    Sadi, Toufik; Oksanen, Jani; Tulkki, Jukka [Department of Biomedical Engineering and Computational Sciences, Aalto University, P.O. Box 12200, FI-00076 Aalto (Finland)

    2013-12-14T23:59:59.000Z

    Recent experimental work has shown significant luminescence enhancement from near-surface quantum-well (QW) structures using metallic grating to convert surface plasmon (SP) modes into radiative modes. This work introduces a detailed theoretical study of plasmonic losses and the role of SPs in improving light extraction from grated light-emitting QW structures, using the fluctuational electrodynamics method. The method explains experimental results demonstrating emission enhancement, light scattering, and plasmonic coupling in the structures. We study these effects in angle-resolved reflectometry and luminescence setups in InGaN QW structures with silver grating. In contrast to experiments, our model allows direct calculation of the optical losses. The model predicts that the plasmonic coupling and scattering increases light emission by a factor of up to three compared to a flat semiconductor structure. This corresponds to reducing the absorption losses from approximately 93% in the ungrated metallic structure to 75% in the grated structure. Lower losses are associated with a significant emission enhancement enabled by the SPs of silver/GaN interfaces, which are present in the blue/green wavelength range, and can be optimized by carefully nanostructuring the metal layer and by the positioning of the QW. In general, the enhancement results from the interplay of mode scattering, conversion of SP energy directly into light, and losses in the metallic grating. The reported losses are very high when compared to the losses present in modern light-emitting diodes (LEDs). Albeit, our work provides tools needed for further optimization of plasmonic light extraction, eventually leading to highly efficient LEDs.

  5. Reduce Radiation Losses from Heating Equipment

    SciTech Connect (OSTI)

    Not Available

    2006-01-01T23:59:59.000Z

    This DOE Industrial Technologies Program tip sheet describes how to save energy and costs by reducing expensive heat losses from industrial heating equipment, such as furnaces.

  6. Analysis of TPV Network Losses (a Presentation)

    SciTech Connect (OSTI)

    DM DePoy; MW Dashiell; DD Rahner; LR Danielson; JE Oppenlander; JL Vell; RJ Wehrer

    2004-12-08T23:59:59.000Z

    This talk focuses on the theoretical analysis of electrical losses associated with electrically networking large numbers of TPV cells to produce high power TPV power generators.

  7. Beam Cooling with ionisation losses

    E-Print Network [OSTI]

    C. Rubbia; A. Ferrari; Y. Kadi; V. Vlachoudis

    2006-02-03T23:59:59.000Z

    A novel type of particle "cooling", called Ionization Cooling, is applicable to slow (v of the order of 0.1c) ions stored in a small ring. The many traversals through a thin foil enhance the nuclear reaction probability, in a steady configuration in which ionisation losses are recovered at each turn by a RF-cavity. For a uniform target "foil" the longitudinal momentum spread diverges exponentially since faster (slower) particles ionise less (more) than the average. In order to "cool" also longitudinally, a chromaticity has to be introduced with a wedge shaped "foil". Multiple scattering and straggling are then "cooled" in all three dimensions, with a method similar to the one of synchrotron cooling, but valid for low energy ions. Particles then stably circulate in the beam indefinitely, until they undergo for instance nuclear processes in the thin target foil. This new method is under consideration for the nuclear production of a few MeV/A ion beams. Simple reactions, for instance Li 7 + D Li 8 + p, are more favourably exploited with the heavier ion colliding against a gas-jet D2 target. Kinematics is generally very favourable, with emission angles in a narrow angular cone and a relatively concentrated outgoing energy spectrum which allows an efficient collection as a neutral gas in a tiny volume with a technology at high temperatures perfected at ISOLDE. It is however of a much more general applicability. The method appears capable of producing a "table top" storage ring with an accumulation rate in excess of 10**14 Li-8 radioactive ion/s for possible use for radioactive beams for physics studies (for example for beta-beams) or for therapy.

  8. Fast pulsing of an open research thermionic converter

    SciTech Connect (OSTI)

    Svensson, R. [Coll. of Applied Engineering and Maritime Studies, Goeteborg (Sweden); [Chalmers Univ. of Technology, Goeteborg (Sweden); Holmlid, L. [Univ. of Goeteborg (Sweden). Dept. of Chemistry

    1997-12-31T23:59:59.000Z

    Several experiments concerning anomalous phenomena in an open Thermionic Energy Converter (TEC) have previously been reported. Under certain conditions a very high electron current (back current), flowing from the cold collector to the hot emitter, has been observed. This phenomenon has been studied with various methods. The conclusion is that an excited form of matter, with a very low work function, is located on the collector surface and in the interelectrode space. The matter consists of highly excited cesium atoms in a condensed form, and is referred to as Rydberg matter (RM). The existence of RM has been predicted theoretically by Manykin, et al. The efficiency of the RM TEC varies considerably with parameters such as emitter temperature and collector temperature. There is also a discrepancy between the apparent collector work function when the collector is run as electron emitter and when it is used as an electron collector. From other experiments the authors conclude that negative ions Cs{sup {minus}} will form on the RM surface on the collector. In order to control the effect of possible negative ions, a series of experiments including rapid pulsing of the TEC is in progress. The objective of the pulsing is to use a negative pulse (with respect to the collector) to remove possible negative ions from the RM surface and restore the low work function of the RM surface.

  9. Advanced Gate Drive for the SNS High Voltage Converter Modulator

    SciTech Connect (OSTI)

    Nguyen, M.N.; Burkhart, C.; Kemp, M.A.; /SLAC; Anderson, D.E.; /Oak Ridge

    2009-05-07T23:59:59.000Z

    SLAC National Accelerator Laboratory is developing a next generation H-bridge switch plate [1], a critical component of the SNS High Voltage Converter Modulator [2]. As part of that effort, a new IGBT gate driver has been developed. The drivers are an integral part of the switch plate, which are essential to ensuring fault-tolerant, high-performance operation of the modulator. The redesigned driver improves upon the existing gate drive in several ways. The new gate driver has improved fault detection and suppression capabilities; suppression of shoot-through and over-voltage conditions, monitoring of dI/dt and Vce(sat) for fast over-current detection and suppression, and redundant power isolation are some of the added features. In addition, triggering insertion delay is reduced by a factor of four compared to the existing driver. This paper details the design and performance of the new IGBT gate driver. A simplified schematic and description of the construction are included. The operation of the fast over-current detection circuits, active IGBT over-voltage protection circuit, shoot-through prevention circuitry, and control power isolation breakdown detection circuit are discussed.

  10. Converting acoustic energy into useful other energy forms

    DOE Patents [OSTI]

    Putterman, Seth J. (Sherman Oaks, CA); Barber, Bradley Paul (Northridge, CA); Hiller, Robert Anthony (Los Angeles, CA); Lofstedt, Ritva Maire Johanna (Los Angeles, CA)

    1997-01-01T23:59:59.000Z

    Sonoluminescence is an off-equilibrium phenomenon in which the energy of a resonant sound wave in a liquid is highly concentrated so as to generate flashes of light. The conversion of sound to light represents an energy amplification of eleven orders of magnitude. The flashes which occur once per cycle of the audible or ultrasonic sound fields can be comprised of over one million photons and last for less 100 picoseconds. The emission displays a clocklike synchronicity; the jitter in time between consecutive flashes is less than fifty picoseconds. The emission is blue to the eye and has a broadband spectrum increasing from 700 nanometers to 200 nanometers. The peak power is about 100 milliWatts. The initial stage of the energy focusing is effected by the nonlinear oscillations of a gas bubble trapped in the liquid. For sufficiently high drive pressures an imploding shock wave is launched into the gas by the collapsing bubble. The reflection of the shock from its focal point results in high temperatures and pressures. The sonoluminescence light emission can be sustained by sensing a characteristic of the emission and feeding back changes into the driving mechanism. The liquid is in a sealed container and the seeding of the gas bubble is effected by locally heating the liquid after sealing the container. Different energy forms than light can be obtained from the converted acoustic energy. When the gas contains deuterium and tritium there is the feasibility of the other energy form being fusion, namely including the generation of neutrons.

  11. Intensive neutrino source on the base of lithium converter

    E-Print Network [OSTI]

    Lyashuk, V I

    2015-01-01T23:59:59.000Z

    An intensive antineutrino source with a hard spectrum (with energy up to 13 MeV, average energy 6.5 MeV) can be realized on the base of beta-decay of short living isotope 8Li (0.84 s). The 8Li isotope (generated in activation of 7Li isotope) is a prime perspective antineutrino source owing to the hard antineutrino spectrum and square dependence of cross section on the energy. Up today nuclear reactors are the most intensive neutrino sources. Antineutrino reactor spectra have large uncertainties in the summary antineutrino spectrum at energy E>6 MeV. Use of 8Li isotope allows to decrease sharply the uncertainties or to exclude it completely. An intensive neutron fluxes are requested for rapid generation of 8Li isotope. The installations on the base of nuclear reactors can be an alternative for nuclear reactors as traditional neutron sources. It is possible creation of neutrino sources another in principle: on the base of tandem of accelerators, neutron generating targets and lithium converter. An intensive neu...

  12. Digital regulation of a phase controlled power converter

    SciTech Connect (OSTI)

    Schultheiss, C.; Haque, T.

    1995-12-01T23:59:59.000Z

    The Relativistic Heavy Ion Collider, now in construction at Brookhaven National Laboratory, will use phase controlled power converters for the main dipole and quadrupole magnet strings. The rectifiers in these power supplies will be controlled by a digital regulator based on the TI 320C30 Digital Signal Processor (DSP). The DSP implements the current loop, the voltage loop, and a system to actively reduce the sub-harmonic ripple components. Digital firing circuits consisting of a phase locked lop and counters are used to fire the SCRs. Corrections for the sub-harmonic reduction are calculated by the DSP and stored in registers in the firing circuit. These corrections are added in hardware, to the over-all firing count provided by the DSP. the resultant count is compared to a reference counter to fire the SCRs. This combination of a digital control system and the digital firing circuits allows the correction of the sub-harmonics in a real-time sense. A prototype of the regulator has been constructed, and the preliminary testing indicates a sub-harmonic reduction of 60 dB.

  13. A Novel Predictive Inductor Multiplier for Integrated Circuit DC-DC Converters in Portable Applications

    E-Print Network [OSTI]

    Rincon-Mora, Gabriel A.

    that the converter appears to have an induct- ance thirty-eight times the value actually used. Compensating for small voltage. This is a major limitation in very common situations like when a Lithium ion battery in the three is a switched capacitor converter, also called a charge pump. In these topologies, one or more capacitors

  14. The method of creating a small interelectrode spacing in thermionic energy converters

    SciTech Connect (OSTI)

    Kalandarishvili, A.G. [Russian Research Center Kurchatov Inst., Moscow (Russian Federation)

    1996-12-31T23:59:59.000Z

    The method is proposed for creating a small interelectrode spacing in thermionic energy converters (TEC) using graphite-based laminated structures placed inside the converter interelectrode gap. The paper discusses conceptual design and fabrication technology of this device. The proposed method is compared with the methods currently implemented in practice.

  15. Non-Droop Methods for Context-Sensitive Sharing in Multi-Module Switching Converters

    E-Print Network [OSTI]

    Kimball, Jonathan W.

    Non-Droop Methods for Context-Sensitive Sharing in Multi-Module Switching Converters Philip T droop or voltage droop controls support context-sensitive sharing. Droop gains can be set readily is to elucidate non-droop approaches that support context-sensitive sharing in various modular converter

  16. Converter and Inductor Design for Fast-Response Microprocessor Power Delivery

    E-Print Network [OSTI]

    Converter and Inductor Design for Fast-Response Microprocessor Power Delivery G. J. Mehas K. D be obtained from the IEEE. #12;Converter and Inductor Design for Fast-Response Microprocessor Power Delivery such as microprocessor power delivery are analyzed, with an emphasis on the role of the inductor. Opti- mum values

  17. Coordination of Converter and Fuel Cell Controllers Kyung-Won Suh and Anna G. Stefanopoulou

    E-Print Network [OSTI]

    Stefanopoulou, Anna

    , such as an air delivery system which supplies oxygen using a compressor or a blower, a hydrogen delivery system with a compressor and a DC-DC converter. We then employ model-based control techniques to tune two separate controllers for the compressor and the converter. We demonstrate that the lack of communication

  18. Development of a Wireless Control and Monitoring System for Wave Energy Converters

    E-Print Network [OSTI]

    Wood, Stephen L.

    Development of a Wireless Control and Monitoring System for Wave Energy Converters Ismail Sultan Control and Monitoring Unit (PCMU) for the design and performance evaluation of wave energy converters (WECs). A prototype PCMU system was successfully deployed on June 8th , 2012 with wave energy convertor

  19. Control of high power IGBT modules in the active region for fast pulsed power converters

    E-Print Network [OSTI]

    Cravero, JM; Garcia Retegui, R; Maestri, S; Uicich, G

    2014-01-01T23:59:59.000Z

    At CERN, fast pulsed power converters are used to supply trapezoidal current in different magnet loads. These converters perform output current regulation by using a high power IGBT module in its ohmic region. This paper presents a new strategy for pulsed current control applications using a specifically designed IGBT driver.

  20. Multi-Stage Converters: A New Technology for Traction Drive Juan W. Dixon

    E-Print Network [OSTI]

    Catholic University of Chile (Universidad Catlica de Chile)

    demonstrated the feasibility to build multi-stage converters for real electric vehicles or electric buses System". 1. Introduction Power Electronics technologies contribute with important part in the development of electric vehicles. On the other hand, the PWM techniques used today to control modern static converters

  1. FC/Battery Power Management for Electric Vehicle Based Interleaved dc-dc Boost Converter Topology

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    FC/Battery Power Management for Electric Vehicle Based Interleaved dc- dc Boost Converter Topology.fr Keywords Fuel cell System (FCS), Electric vehicle, Energy management, Interleaved Boost DC-DC Converter (FC for electric vehicle may not be feasible to satisfy the peak demand changes especially during accelerations

  2. Regenerative Braking for an Electric Vehicle Using Ultracapacitors and a Buck-Boost Converter

    E-Print Network [OSTI]

    Catholic University of Chile (Universidad Catlica de Chile)

    Regenerative Braking for an Electric Vehicle Using Ultracapacitors and a Buck-Boost Converter Juan for an Electric Vehicle has been simulated. The purpose of this device is to allow higher accelerations, similar in shape and size to a Chevrolet S-10. This vehicle was already converted to an electric car

  3. Generalized Steady-state Analysis of Multiphase Interleaved Boost Converter with Coupled Inductors

    E-Print Network [OSTI]

    Lipo, Thomas

    2005-38 Generalized Steady-state Analysis of Multiphase Interleaved Boost Converter with Coupled-dong, Masan, Gyeongnam, 631-701, Republic of Korea #12;Generalised steady-state analysis of multiphase.A. Lipo Abstract: The generalised steady-state analysis of the multi-phase interleaved boost converter

  4. Digitally Controlled Distributed Multiphase DC-DC Converters Xu Zhang, Luca Corradini and Dragan Maksimovic

    E-Print Network [OSTI]

    Digitally Controlled Distributed Multiphase DC-DC Converters Xu Zhang, Luca Corradini and Dragan, corradin, maksimov}@colorado.edu Abstract -- This paper describes a distributed master-slave multiphase DC V-to-12 V input, 1.3 V, 20 A output two-phase synchronous buck converter. Index Terms-- Multiphase

  5. Comparison of Two Autonomous AC-DC Converters for Piezoelectric Energy Scavenging Systems

    E-Print Network [OSTI]

    Boyer, Edmond

    - 1 - Comparison of Two Autonomous AC-DC Converters for Piezoelectric Energy Scavenging Systems E Cornaredo, Milan, Italy Abstract - Piezoelectric Energy Scavenging Systems (PESS) are used to convert of the output voltage of these transducers is needed. Since the output power level of the energy transducer can

  6. Sliding Mode Control of Boost Converter: Application to energy storage system via supercapacitors

    E-Print Network [OSTI]

    Boyer, Edmond

    Sliding Mode Control of Boost Converter: Application to energy storage system via supercapacitors of an energy storage system based on supercapacitors technology in order to regulate the output voltage. Given, classical PID controllers are used for the control of power converters [1], [2], [3]. Simple models

  7. Boost Converter Provides Temperature-Controlled Operation of 12V Fan from +5V Supply

    E-Print Network [OSTI]

    McNeill, John A.

    enclosure, and reducing the fan supply voltage when maximum cooling is not necessary. Reducing the operatingBoost Converter Provides Temperature-Controlled Operation of 12V Fan from +5V Supply John Mc converter shown in Fig. 1 allows operation of a 12V brushless DC fan from a +5V supply. The circuit is based

  8. Solar Power To Help Convert Carbon Dioxide Into Fuel : Renewable Energy News

    E-Print Network [OSTI]

    Lovley, Derek

    Solar Power To Help Convert Carbon Dioxide Into Fuel : Renewable Energy News TUESDAY 25 MAY, 2010 | | Solar Power To Help Convert Carbon Dioxide Into Fuel by Energy Matters Microbiologist Derek Lovley dioxide into transportation fuels, with the help of special micro-organisms and solar power. The team

  9. Digital Background Calibration of an Algorithmic Analog-to-Digital Converter

    E-Print Network [OSTI]

    Hurst, Paul J.

    one sample-and-hold amplifier. At a sampling rate of 20 Msamples/s, the peak signal-to-noise-effective design of high-performance analog-to-digital converters with low-performance op amps. In this paper analog-to-digital converter (ADC). To minimize power dissipation and noise, the queue consists of only

  10. Design and development of a DC-DC converter for a fuel cell inverter system

    E-Print Network [OSTI]

    Gopinath, Rajesh

    2001-01-01T23:59:59.000Z

    This thesis outlines the design and development of a DC-DC converter for a fuel cell inverter application. The proposed DC-DC converter was designed and tested at Texas A&M to meet the specifications laid down for the '2001 Future Energy Challenge...

  11. The Valuation of Convertible Bonds With Credit Risk P. A. Forsyth K. R. Vetzal

    E-Print Network [OSTI]

    Forsyth, Peter A.

    The Valuation of Convertible Bonds With Credit Risk E. Ayache P. A. Forsyth K. R. Vetzal April 22 upon the history of its stock price. This paper explores the valuation of convertible bonds subject implicit method to decou- ple the system of linear complementarity problems at each timestep. Numerical

  12. An 8-bit current mode ripple folding analog to digital converter

    E-Print Network [OSTI]

    Dinc, Huseyin

    2002-01-01T23:59:59.000Z

    Design of an 8-bit current mode, ripple-folding analog to digital (A/D) converter is discussed. The ripple folding technique and the possible implementations in different process technologies are summarized. To have an A/D converter compatible...

  13. Design of high speed low voltage data converters for UWB communication systems

    E-Print Network [OSTI]

    Lee, Choong Hoon

    2006-08-16T23:59:59.000Z

    For A/D converters in ultra-wideband (UWB) communication systems, the flash A/D type is commonly used because of its fast speed and simple architecture. However, the number of comparators in a flash A/D converter exponentially increases...

  14. An 8-bit current mode ripple folding analog to digital converter

    E-Print Network [OSTI]

    Dinc, Huseyin

    2002-01-01T23:59:59.000Z

    Design of an 8-bit current mode, ripple-folding analog to digital (A/D) converter is discussed. The ripple folding technique and the possible implementations in different process technologies are summarized. To have an A/D converter compatible...

  15. A Passivity-Based Controller for coordination of converters in a Fuel Cell System

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    and hybrid vehicles has increased since 2009. In this context, the development of a fuel cell (FC) system, , A Passivity-Based Controller for coordination of converters in a Fuel Cell System M. Hilaireta-mail: mickael.hilairet@lgep.supelec.fr Abstract The problem of converters coordination of a fuel cell system

  16. Wide input range DC-DC converter with digital control scheme

    E-Print Network [OSTI]

    Harfman Todorovic, Maja

    2006-04-12T23:59:59.000Z

    In this thesis analysis and design of a wide input range DC-DC converter is proposed along with a robust power control scheme. The proposed converter and its control is designed to be compatible to a fuel cell power source, which exhibits 2...

  17. FLATNESS BASED CONTROL OF A BUCK-CONVERTER DRIVEN DC MOTOR

    E-Print Network [OSTI]

    Knobloch,Jrgen

    FLATNESS BASED CONTROL OF A BUCK-CONVERTER DRIVEN DC MOTOR Felix Antritter ,1 Peter Maurer Johann on the circuit and control design of a buck converter driven DC motor. The steps of design, as for example objective: tracking control of the DC motor's shaft angular velocity. The dynamic system composed from

  18. MODULAR MULTI-LEVEL CONVERTER BASED HVDC SYSTEM FOR GRID CONNECTION OF OFFSHORE WIND

    E-Print Network [OSTI]

    Chaudhary, Sanjay

    MODULAR MULTI-LEVEL CONVERTER BASED HVDC SYSTEM FOR GRID CONNECTION OF OFFSHORE WIND POWER PLANT U off-shore wind power plants. The MMC consists of a large number of simple voltage sourced converter offshore wind power plants (WPP) because they offer higher energy yield due to a superior wind profile

  19. Ga{sub x}In{sub 1{minus}x}As thermophotovoltaic converters

    SciTech Connect (OSTI)

    Wanlass, M.W.; Ward, J.S.; Emery, K.A.; Coutts, T.J. [National Renewable Energy Lab., Golden, CO (United States)

    1994-12-31T23:59:59.000Z

    Preliminary research into the development of single-junction Ga{sub x}In{sub 1{minus}x}As thermophotovoltaic (TPV) power converters is reviewed. The devices structures are grown epitaxially on single-crystal InP substrates. Converter band gaps of 0.50--0.74 eV have been considered in accordance with modeling calculations. A 1-sun, AMO efficiency of 12.8% is reported for a lattice-matched, 0.74-eV converter. Converters with lower band gaps are fabricated using lattice-mismatched, compositionally graded structures. Functional TPV converters with good performance characteristics have been demonstrated for band gaps as low as 0.5 eV.

  20. Utility-Scale Power Router: Dynamic Control of Grid Assets Using Direct AC Converter Cells

    SciTech Connect (OSTI)

    None

    2010-09-01T23:59:59.000Z

    ADEPT Project: Georgia Tech is developing a cost-effective, utility-scale power router that uses an enhanced transformer to more efficiently direct power on the grid. Existing power routing technologies are too expensive for widespread use, but the ability to route grid power to match real-time demand and power outages would significantly reduce energy costs for utilities, municipalities, and consumers. Georgia Tech is adding a power converter to an existing grid transformer to better control power flows at about 1/10th the cost of existing power routing solutions. Transformers convert the high-voltage electricity that is transmitted through the grid into the low-voltage electricity that is used by homes and businesses. The added converter uses fewer steps to convert some types of power and eliminates unnecessary power storage, among other improvements. The enhanced transformer is more efficient, and it would still work even if the converter fails, ensuring grid reliability.

  1. Compact self-contained electrical-to-optical converter/transmitter

    SciTech Connect (OSTI)

    Seligmann, D.A.; Moss, W.C.; Valk, T.C.; Conder, A.D.

    1992-12-31T23:59:59.000Z

    An electrical-to-optical converter/transmitter is disclosed. A first optical receiver and a second optical receiver are provided for receiving a calibrate command and a power switching signal, respectively, from a remote processor. A third receiver is provided for receiving an analog electrical signal from a transducer. A calibrator generates a reference signal in response to the calibrate command. A combiner mixes the electrical signal with the reference signal to form a calibrated signal. A converter converts the calibrated signal to an optical signal. A transmitter transmits the optical signal to the remote processor. A primary battery supplies power to the calibrator, the combiner, the converter, and the transmitter. An optically-activated switch supplies power to the calibrator, the combiner, the converter, and the transmitter in response to the power switching signal. An auxiliary battery supplies power continuously to the switch means.

  2. Switching coordination of distributed dc-dc converters for highly efficient photovoltaic power plants

    DOE Patents [OSTI]

    Agamy, Mohammed; Elasser, Ahmed; Sabate, Juan Antonio; Galbraith, Anthony William; Harfman Todorovic, Maja

    2014-09-09T23:59:59.000Z

    A distributed photovoltaic (PV) power plant includes a plurality of distributed dc-dc converters. The dc-dc converters are configured to switch in coordination with one another such that at least one dc-dc converter transfers power to a common dc-bus based upon the total system power available from one or more corresponding strings of PV modules. Due to the coordinated switching of the dc-dc converters, each dc-dc converter transferring power to the common dc-bus continues to operate within its optimal efficiency range as well as to optimize the maximum power point tracking in order to increase the energy yield of the PV power plant.

  3. Efficient spin transfer torque in La{sub 2/3}Sr{sub 1/3}MnO{sub 3} nanostructures

    SciTech Connect (OSTI)

    Foerster, Michael [Institut fr Physik, Johannes Gutenberg-Universitt, Staudingerweg 7, 55128 Mainz (Germany); ALBA Synchrotron light source, Carrretera BP 1413, km 3.3, 08290 Cerdanyola del Valles, Barcelona (Spain); Pea, Luis; Finizio, Simone; Schulz, Tomek; Bisig, Andr [Institut fr Physik, Johannes Gutenberg-Universitt, Staudingerweg 7, 55128 Mainz (Germany); Vaz, C. A. F. [Institut fr Physik, Johannes Gutenberg-Universitt, Staudingerweg 7, 55128 Mainz (Germany); SwissFEL, Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Heinen, Jan [Fachbereich Physik, Universitt Konstanz, Universittsstrae 10, 78457 Konstanz (Germany); Bttner, Felix [Institut fr Physik, Johannes Gutenberg-Universitt, Staudingerweg 7, 55128 Mainz (Germany); Institut fr Optik und Atomare Physik, Technische Universitt Berlin, Strae des 17. Juni 135, 10623 Berlin (Germany); Eisebitt, Stefan [Institut fr Optik und Atomare Physik, Technische Universitt Berlin, Strae des 17. Juni 135, 10623 Berlin (Germany); Mchin, Laurence [GREYC, UMR 6072, CNRS-ENSICAEN-UCBN, 6 Boulevard du Marchal Juin, Caen Cedex 14050 (France); and others

    2014-02-17T23:59:59.000Z

    We carry out low temperature magnetotransport measurements on nanostructured La{sub 2/3}Sr{sub 1/3}MnO{sub 3} wires to study the interaction between spin-polarized current and magnetization in this half metallic material. We selectively position domain walls by applying external fields. The domain wall resistance is found to be positive, in contrast to conventional 3d metals. The depinning field is reduced when current pulses are injected into the wire. By comparing measurements for both current polarities, we can disentangle heating and spin transfer torque effects. The determined spin transfer torque efficiency is of the order of 4??10{sup ?14} Tm{sup 2}/A, which is significantly higher than in permalloy.

  4. Kalman Filtering in Correlated Losses Sachin Adlakha

    E-Print Network [OSTI]

    Adlakha, Sachin

    Kalman Filtering in Correlated Losses Sachin Adlakha Department of Electrical Engineering Stanford in presence of correlated losses using a Kalman Filter . This scenario arises in performing vehicle tracking for the Kalman estimator to lose some observations. We study the behavior of Kalman filter in such correlated

  5. > MEPS06 Preprint Version Transmission Loss

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    .phulpin@supelec.fr Abstract - In the deregulated electrical power system, the allocation of transmission losses is becoming a key issue. The electric transmission power system is more and more constrained due to the increasing electrical power system, the allocation of transmission losses is becoming a key issue. The electric

  6. MANAGING JOB LOSS and FINANCIAL STRESS

    E-Print Network [OSTI]

    MANAGING JOB LOSS and FINANCIAL STRESS a Personal and Family Guide CENTER ON THE FAMILY #12;2 Managing Job Loss and Financial Stress The issues associated with losing one's job or having hours cut also have other assistance (e.g., job placement, resume preparation, retraining), of which you should

  7. CLASSICAL CEPHEIDS REQUIRE ENHANCED MASS LOSS

    SciTech Connect (OSTI)

    Neilson, Hilding R.; Langer, Norbert; Izzard, Robert [Argelander Institute for Astronomy, University of Bonn, Auf dem Huegel 71, D-53121 Bonn (Germany); Engle, Scott G.; Guinan, Ed, E-mail: neilsonh@etsu.edu [Department of Astronomy and Astrophysics, Villanova University, 800 Lancaster Ave. Villanova, PA 19085 (United States)

    2012-11-20T23:59:59.000Z

    Measurements of rates of period change of Classical Cepheids probe stellar physics and evolution. Additionally, better understanding of Cepheid structure and evolution provides greater insight into their use as standard candles and tools for measuring the Hubble constant. Our recent study of the period change of the nearest Cepheid, Polaris, suggested that it is undergoing enhanced mass loss when compared to canonical stellar evolution model predictions. In this work, we expand the analysis to rates of period change measured for about 200 Galactic Cepheids and compare them to population synthesis models of Cepheids including convective core overshooting and enhanced mass loss. Rates of period change predicted from stellar evolution models without mass loss do not agree with observed rates, whereas including enhanced mass loss yields predicted rates in better agreement with observations. This is the first evidence that enhanced mass loss as suggested previously for Polaris and {delta} Cephei must be a ubiquitous property of Classical Cepheids.

  8. Heat loss from an open cavity

    SciTech Connect (OSTI)

    McDonald, C.G. [California State Polytechnic Univ., Pomona, CA (United States). Coll. of Engineering

    1995-12-01T23:59:59.000Z

    Cavity type receivers are used extensively in concentrating solar thermal energy collecting systems. The Solar Total Energy Project (STEP) in Shenandoah, Georgia is a large scale field test for the collection of solar thermal energy. The STEP experiment consists of a large field array of solar collectors used to supplement the process steam, cooling and other electrical power requirements of an adjacent knitwear manufacturing facility. The purpose of the tests, conducted for this study, was to isolate and quantify the radiative, conductive, and convective components of total heat loss, and to determine the effects of operating temperature, receiver angle, and aperture size on cavity heat loss. An analytical model for radiative heat loss was developed and compared with two other methods used to determine radiative heat loss. A proposed convective heat loss correlation, including effects of aperture size, receiver operating temperature, and receiver angle is presented. The resulting data is a source to evaluate the STEP measurements.

  9. Study of Power Converter Topologies with Energy Recovery and grid power flow control Part B: boost converter with energy storage

    E-Print Network [OSTI]

    Rogelio, Garcia Retegui; Gustavo, Uicich; Mario, Benedetti; Gilles, Le Godec; Konstantinos, Papastergiou

    2015-01-01T23:59:59.000Z

    In the framework of a Transfer line (TT2) Consolidation Programme, a number of studies on Energy cycling have been commissioned. Part of this work involves the study of dierent power electronic system topologies for magnet energy recovery. In this report, the use of a boost front-end converter supplying DC link of a 4-quadrant magnet supply is analysed. The key objective of the study is to find control strategies that result in the control of the peak power required from the power network as well as to recover the magnet energy into capacitor banks with controlled voltage fluctuation. The study comprises the modelling of the system by means of the method of state averaging and the development of regulation strategies to energy management. The proposed control strategies can be divided in two groups: in the first group, the magnet current is used to define the reference for the control system, while in the second group this current is unknown and some strategies are devised to limit the power drawn from the el...

  10. Design and analysis of a zero-voltage switching scheme for a dc- to-dc converter

    E-Print Network [OSTI]

    Arun, G.

    1992-01-01T23:59:59.000Z

    5S 59 VITA . 65 I. IST OF FICI;RES FIGURE Page Linear versus switch-mode power convers&on Components of a switch-mode dc-to-dc converter 3 A typical dc-to-dc converter system Basic buck converter Basic boost converter Basic buck...-boost converter 7 One leg of a, dc-to-dc converter. Turn-on and turn-off scenartos in switch-mode operation. 16 10 Switching loci in the ur ? ir plane. Circuit for. zero-voltage sw&tching. . Mode 1 17 90 Mode? Mode I Mode 5 oo 93 Typical voltage...

  11. Collisionality Scaling of Main-ion Toroidal and Poloidal Rotation in Low Torque DIII-D Plasmas

    SciTech Connect (OSTI)

    B A Grierson, et al

    2013-05-10T23:59:59.000Z

    In tokamak plasmas with low levels of toroidal rotation, the radial electric fi eld Er is a combination of pressure gradient and toroidal and poloidal rotation components, all having similar magnitudes. In order to assess the validity of neoclassical poloidal rotation theory for determining the poloidal rotation contribution to Er , D? emission from neutral beam heated tokamak discharges in DIII-D [J.L. Luxon, Nucl. Fusion 42 , 614 (2002)] has been evaluated in a sequence of low torque (electron cyclotron resonance heating and balanced diagnostic neutral beam pulse) discharges to determine the local deuterium toroidal rotation velocity. By invoking the radial force balance relation the deuterium poloidal rotation can be inferred. It is found that the deuterium poloidal low exceeds the neoclassical value in plasmas with collisionality #23;#3; ?i < 0: 1, being more ion diamagnetic, and with a stronger dependence on collisionality than neoclassical theory predicts. At low toroidal rotation, the poloidal rotation contribution to the radial electric fi eld and its shear is signi cant. The eff ect of anomalous levels of poloidal rotation on the radial electric fi eld and cross fi eld heat transport is investigated for ITER parameters.

  12. Flows and torques in Brownian ferrofluids subjected to rotating uniform magnetic fields in a cylindrical and annular geometry

    SciTech Connect (OSTI)

    Torres-Diaz, I.; Cortes, A.; Rinaldi, C., E-mail: carlos.rinaldi@bme.ufl.edu [Department of Chemical Engineering, University of Puerto Rico, Mayagez, Puerto Rico 00681-9000 (United States); Cedeo-Mattei, Y. [Department of Chemistry, University of Puerto Rico, Mayagez, Puerto Rico 00681-9019 (United States)] [Department of Chemistry, University of Puerto Rico, Mayagez, Puerto Rico 00681-9019 (United States); Perales-Perez, O. [Department of Engineering Science and Materials, University of Puerto Rico, Mayagez, Puerto Rico 00681-9044 (United States)] [Department of Engineering Science and Materials, University of Puerto Rico, Mayagez, Puerto Rico 00681-9044 (United States)

    2014-01-15T23:59:59.000Z

    Ferrofluid flow in cylindrical and annular geometries under the influence of a uniform rotating magnetic field was studied experimentally using aqueous ferrofluids consisting of low concentrations (<0.01 v/v) of cobalt ferrite nanoparticles with Brownian relaxation to test the ferrohydrodynamic equations, elucidate the existence of couple stresses, and determine the value of the spin viscosity in these fluids. An ultrasound technique was used to measure bulk velocity profiles in the spin-up (cylindrical) and annular geometries, varying the intensity and frequency of the rotating magnetic field generated by a two pole stator winding. Additionally, torque measurements in the cylindrical geometry were made. Results show rigid-body like velocity profiles in the bulk, and no dependence on the axial direction. Experimental velocity profiles were in quantitative agreement with the predictions of the spin diffusion theory, with a value of the spin viscosity of ?10{sup ?8} kgm/s, two orders of magnitude larger than the value estimated earlier for iron oxide based ferrofluids, and 12 orders of magnitude larger than estimated using dimensional arguments valid in the infinite dilution limit. These results provide further evidence of the existence of couple stresses in ferrofluids and their role in driving the spin-up flow phenomenon.

  13. Sender-Based Heuristics for Distinguishing Congestion Losses from Wireless Transmission Losses

    E-Print Network [OSTI]

    Vaidya, Nitin

    Sender-Based Heuristics for Distinguishing Congestion Losses from Wireless Transmission Losses Saad-3112, USA E-mail: saadb@cs.tamu.edu Phone : (409) 845-5007 Fax : (409) 847-8578 Technical Report #98-013 Abstract TCP is a popular transport protocol used in present-day internet. When packet losses occur, TCP

  14. Differentiated Services: A New Direction for Distinguishing Congestion Losses from Wireless Losses

    E-Print Network [OSTI]

    Differentiated Services: A New Direction for Distinguishing Congestion Losses from Wireless Losses Sa^ad Biaz Nitin H. Vaidya ¡£¢ sbiaz@eng.auburn.edu nhv@crhc.uiuc.edu February 21, 2003 Technical Report # CSSE03-02 Abstract Currently, a TCP sender considers all losses as congestion signals and reacts

  15. AC Losses of Prototype HTS Transmission Cables

    SciTech Connect (OSTI)

    Demko, J.A.; Dresner, L.; Hughey, R.L.; Lue, J.W.; Olsen, S.K.; Sinha, U.; Tolbert, J.C.

    1998-09-13T23:59:59.000Z

    Since 1995 Southwire Company and Oak Ridge National Laboratory (ORNL) have jointly designed, built, and tested nine, l-m long, high temperature superconducting (HTS) transmission cable prototypes. This paper summarizes the AC loss measurements of five of the cables not reported elsewhere, and compares the losses with each other and with theory developed by Dresner. Losses were measured with both a calorimetric and an electrical technique. Because of the broad resistive transition of the HTS tapes, the cables can be operated stably beyond their critical currents. The AC losses were measured in this region as well as below critical currents. Dresner's theory takes into account the broad resistive transition of the HTS tapes and calculates the AC losses both below and above the critical current. The two sets of AC 10SS data agree with each other and with the theory quite welL In particular, at low currents of incomplete penetration, the loss data agree with the theoretical prediction of hysteresis loss based on only the outer two Iayers carrying the total current.

  16. Modeling particle loss in ventilation ducts

    SciTech Connect (OSTI)

    Sippola, Mark R.; Nazaroff, William W.

    2003-04-01T23:59:59.000Z

    Empirical equations were developed and applied to predict losses of 0.01-100 {micro}m airborne particles making a single pass through 120 different ventilation duct runs typical of those found in mid-sized office buildings. For all duct runs, losses were negligible for submicron particles and nearly complete for particles larger than 50 {micro}m. The 50th percentile cut-point diameters were 15 {micro}m in supply runs and 25 {micro}m in return runs. Losses in supply duct runs were higher than in return duct runs, mostly because internal insulation was present in portions of supply duct runs, but absent from return duct runs. Single-pass equations for particle loss in duct runs were combined with models for predicting ventilation system filtration efficiency and particle deposition to indoor surfaces to evaluate the fates of particles of indoor and outdoor origin in an archetypal mechanically ventilated building. Results suggest that duct losses are a minor influence for determining indoor concentrations for most particle sizes. Losses in ducts were of a comparable magnitude to indoor surface losses for most particle sizes. For outdoor air drawn into an unfiltered ventilation system, most particles smaller than 1 {micro}m are exhausted from the building. Large particles deposit within the building, mostly in supply ducts or on indoor surfaces. When filters are present, most particles are either filtered or exhausted. The fates of particles generated indoors follow similar trends as outdoor particles drawn into the building.

  17. A Generalized Class of Stationary Frame-Current Controllers for Grid-Connected ACDC Converters

    E-Print Network [OSTI]

    Hwang, J. George

    Within power systems, high-power pulsewidth-modulated ac-dc converters are used in flexible ac transmission systems controllers and for interfacing renewable energy sources to the grid. These converters traditionally ...

  18. Analysis and design of a direct AC to AC matrix converter topology

    E-Print Network [OSTI]

    Choi, Sewan

    1992-01-01T23:59:59.000Z

    - eration. With the advent of the thyristor and more recent devices such as the Metal oxided semiconductor field effect transistor(MOSI'ET), the Insulated gate bipolar transistor(IGBT) and the MOS controlled thyristor(MCT), it has become increas- ingly... commutated devices such as OTO's, IGBT's, IVIOSFET's and MCT's. The principle of forced commutation is used in clirect ac to ac matrix converter which is described in the next section. B. Direct AC to AC Matrix Converter Direct ac to ac matrix converters...

  19. A High Efficiency DC-DC Converter Topology Suitable for Distributed Large Commercial and Utility Scale PV Systems

    SciTech Connect (OSTI)

    Mohammed S. Agamy; Maja Harfman-Todorovic; Ahmed Elasser; Robert L. Steigerwald; Juan A. Sabate; Song Chi; Adam J. McCann; Li Zhang; Frank Mueller

    2012-09-01T23:59:59.000Z

    In this paper a DC-DC power converter for distributed photovoltaic plant architectures is presented. The proposed converter has the advantages of simplicity, high efficiency, and low cost. High efficiency is achieved by having a portion of the input PV power directly fed forward to the output without being processed by the converter. The operation of this converter also allows for a simplified maximum power point tracker design using fewer measurements

  20. Report on fuel pool water loss tests

    SciTech Connect (OSTI)

    Zalenski, R.F. [West Valley Nuclear Services Co., West Valley, NY (United States)

    1995-12-31T23:59:59.000Z

    To resolve potential concerns on the integrity of the fuel storage pool at the West Valley Demonstration Project (WVDP), a highly accurate testing technique was developed to quantify water losses from the pool. The fuel pool is an unlined, single wall, reinforced concrete structure containing approximately 818,000 gallons of water. Since an initial test indicated that water losses could possibly be attributed solely to evaporation, a cover was suspended and sealed over the pool to block evaporation losses. High accuracy water level and temperature instrumentation was procured and installed. The conclusions of this report indicate that unaccounted-for water losses from the pool are insignificant and there is no detectable leakage within the range of test accuracy.

  1. Telling Absence: War Widows, Loss and Memory

    E-Print Network [OSTI]

    Loipponen, Jaana

    2009-01-01T23:59:59.000Z

    This thesis concerns feminist sociological analysis of war loss and its consequences as experienced and told by Finnish Karelian war widows of World War 2. They lost their partners and had to leave their homes by force, ...

  2. Reduction of Hydrocarbon Losses to Flare Systems

    E-Print Network [OSTI]

    Page, J.

    1979-01-01T23:59:59.000Z

    merit consideration because the losses and associated economic penalties are assumed to be small. Flare gas flow is not easily measured and as a result, most plants are unaware of how much product they are actually losing during normal operation...

  3. Corona losses in HVdc bipolar lines

    SciTech Connect (OSTI)

    Corbellini, U.; Pelacchi, P. [Univ. of Pisa (Italy). Dept. of Electric Systems and Automation] [Univ. of Pisa (Italy). Dept. of Electric Systems and Automation

    1996-07-01T23:59:59.000Z

    The problem related to the prediction of corona losses in HVdc bipolar lines has been solved, in the past, by means of semi-empirical monomial formulae. However, the proposed formulae that are simpler to use do not always give adequate calculation precision, while the formulae that provide the closest results require implicit functions of different complexity, which are difficult to apply; moreover, it is not possible to understand clearly what influence the variations of the different line parameters have on the losses themselves. The new monomial semi-empirical relationship, proposed to predict the corona losses in HVdc bipolar lines, is very simple to use; it highlights the dependence of power losses due to the corona effect by the different line parameters. The formula has been developed by elaborating a considerable amount of available experimental data.

  4. Reducing Livestock Losses To Toxic Plants

    E-Print Network [OSTI]

    McGinty, Allan; Machen, Richard V.

    2000-04-25T23:59:59.000Z

    TexasAgriculturalExtensionService The Texas A&M University System Reducing Livestock Losses to Toxic Plants B-1499 Sand Shinnery L Perennial Broomweed Texas Agricultural Extension Service a71 Zerle L. Carpenter, Director a71 The Texas A&M University... ................... ...... ... 6 BehaviorModification.................................. 7 Management Techniques forReducingToxic Plant Losses... 8 LiteratureCited........................................ 9 Poisonous Plants ofTexas...............................10 Editor: Judy Winn...

  5. Reducing Livestock Losses To Toxic Plants

    E-Print Network [OSTI]

    McGinty, Allan; Machen, Richard V.

    2000-04-25T23:59:59.000Z

    TexasAgriculturalExtensionService The Texas A&M University System Reducing Livestock Losses to Toxic Plants B-1499 Sand Shinnery L Perennial Broomweed Texas Agricultural Extension Service a71 Zerle L. Carpenter, Director a71 The Texas A&M University... ................... ...... ... 6 BehaviorModification.................................. 7 Management Techniques forReducingToxic Plant Losses... 8 LiteratureCited........................................ 9 Poisonous Plants ofTexas...............................10 Editor: Judy Winn...

  6. Traction Drive System for Electric Vehicles, Using Multilevel Converters Juan W. Dixon, Micah Ortzar and Felipe Ros

    E-Print Network [OSTI]

    Catholic University of Chile (Universidad Catlica de Chile)

    Traction Drive System for Electric Vehicles, Using Multilevel Converters Juan W. Dixon, Micah converters for electric vehicles using multilevel inverters. They are being compared with inverters using vehicles. On the other hand, the PWM techniques used today to control modern static converters for electric

  7. Design and analysis of modern three-phase AC/AC power converters for AC drives and utility interface

    E-Print Network [OSTI]

    Kwak, Sangshin

    2005-08-29T23:59:59.000Z

    to the lack of dc electrolytic capacitors, which is very vulnerable in high temperature. The converter also has a long lifetime with no limited-lifetime capacitors [13], [15]. A three-phase matrix converter is shown in Fig. 1.2. The converter configuration...

  8. A resonant load circuit to develop electrical power transfer of thermionic converters

    SciTech Connect (OSTI)

    Perez, G.; Estrada, C.A.; Jimenez, A.E.

    1998-07-01T23:59:59.000Z

    Low internal impedance of thermionic converters requires a low impedance load in the DC mode to obtain optimal power transfer. An internal resistance near 0.1 W for thermionic converters is common. According to the maximum power theorem [Desoer,1969], a similar magnitude for the resistance load must be fixed. Due to temperature changes, the internal plasma resistance and the resistance of the leads is modified [Houston,1959], for this reason, it is difficult to maintain maximum power transfer to the load. This paper presents a resonant load circuit for thermionic converters in the AC mode, to develop impedance coupling. The circuit employs an electrical transformer and positive feedback; by this way, oscillations are themselves maintained. It is used an electrical circuit model [Perez et al, 1997], to simulate the electrical behavior of the thermionic converter.

  9. Fabrication and Testing of Full-Length Single-Cell Externally Fueled Converters for Thermionic Reactors

    SciTech Connect (OSTI)

    Schock, Alfred

    1995-08-01T23:59:59.000Z

    Paper presented at the 29th IECEC in Monterey, CA in August 1994. The present paper describes the fabrication and testing of full-length prototypcial converters, both unfueled and fueled, and presents parametric results of electrically heated tests.

  10. Frequency-based current-sharing techniques for paralleled power converters

    E-Print Network [OSTI]

    Perreault, David J.

    A new current-sharing technique for paralleled power converters, which is based on frequency encoding of the current-sharing information, is introduced. The approach has significant advantages over existing methods, including ...

  11. High efficiency resonant dc/dc converter for solar power applications

    E-Print Network [OSTI]

    Inam, Wardah

    2013-01-01T23:59:59.000Z

    This thesis presents a new topology for a high efficiency dc/dc resonant power converter that utilizes a resistance compression network to provide simultaneous zero voltage switching and near zero current switching across ...

  12. Zero-Crossing-Based Ultra-Low-Power A/D Converters

    E-Print Network [OSTI]

    Lee, Hae-Seung

    Since the first demonstration of a comparator-based switched-capacitor circuit, analog-to-digital (A/D) converters based on virtual ground detection have made steady and significant progress. Comparators have been replaced ...

  13. A zero-crossing based pipelined analog-to-digital converter with supply voltage scalibility

    E-Print Network [OSTI]

    Lee, Sunghyuk

    2010-01-01T23:59:59.000Z

    A zero-crossing based pipelined analog-to-digital converter (ADC) has been designed and is fabricated in a 65nm CMOS process. The highly digital implementation characteristic of the zero-crossing detection technique enables ...

  14. The Utilization and Recovery of Energy from Blast Furnaces and Converters

    E-Print Network [OSTI]

    Hegemann, K. R.; Niess, T.; Baare, R. D.

    1979-01-01T23:59:59.000Z

    comprising a gas cleaning unit for dust removal and a turbine for converting the recoverable thermal energy into mechanical and electrical energy. The adjustable annular gap scrubber for separating fine dust also serves as an element for regulating the gas...

  15. A New Integrated Onboard Charger and Accessory Power Converter for Plug-in Electric Vehicles

    SciTech Connect (OSTI)

    Su, Gui-Jia [ORNL; Tang, Lixin [ORNL

    2014-01-01T23:59:59.000Z

    In this paper, a new approach is presented for integrating the function of onboard battery charging into the traction drive system and accessory dc-dc converter of a plug-in electric vehicle (PEV). The idea is to utilize the segmented traction drive system of a PEV as the frond converter of the charging circuit and the transformer and high voltage converter of the 14 V accessory dc-dc converter to form a galvanically isolated onboard charger. Moreover, a control method is presented for suppressing the battery current ripple component of twice the grid frequency with the reduced dc bus capacitor in the segmented inverter. The resultant integrated charger has lower cost, weight, and volume than a standalone charger due to a substantially reduced component count. The proposed integrated charger topology was verified by modeling and experimental results on a 5.8 kW charger prototype.

  16. Quantification of the influence of directional sea state parameters over the performances of wave energy converters

    E-Print Network [OSTI]

    Pascal, Remy Claude Rene

    2012-11-29T23:59:59.000Z

    Accurate predictions of the annual energy yield from wave energy converters are essential to the development of the wave industry. The current method based on power matrices uses only a small part of the data available ...

  17. Effect of a nonlinear power take off on a wave energy converter

    E-Print Network [OSTI]

    Bailey, Helen Louise

    2011-11-22T23:59:59.000Z

    This thesis is titled The influence of a nonlinear Power Take Off on a Wave Energy Converter. It looks at the effect that having a nonlinear Power Take Off (PTO) has on an inertial referenced, slack moored, point absorber, ...

  18. Request for Information Regarding a Proposed Funding Opportunity for Administration of the Wave Energy Converter Prize

    Broader source: Energy.gov [DOE]

    This announcement is intended to serve as a Notice of Intent of the upcoming Funding Opportunity Announcement (FOA) regarding Administration of the Wave Energy Converter (WEC) Prize and Request for Information to solicit information regarding pote

  19. Compact self-contained electrical-to-optical converter/transmitter

    DOE Patents [OSTI]

    Seligmann, D.A.; Moss, W.C.; Valk, T.C.; Conder, A.D.

    1995-11-21T23:59:59.000Z

    A first optical receiver and a second optical receiver are provided for receiving a calibrate command and a power switching signal, respectively, from a remote processor. A third receiver is provided for receiving an analog electrical signal from a transducer. A calibrator generates a reference signal in response to the calibrate command. A combiner mixes the electrical signal with the reference signal to form a calibrated signal. A converter converts the calibrated signal to an optical signal. A transmitter transmits the optical signal to the remote processor. A primary battery supplies power to the calibrator, the combiner, the converter, and the transmitter. An optically-activated switch supplies power to the calibrator, the combiner, the converter, and the transmitter in response to the power switching signal. An auxiliary battery supplies power continuously to the switch. 13 figs.

  20. Converting Hybrid Wire-frames to B-rep Models Jie-Hui Gong

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Converting Hybrid Wire-frames to B-rep Models Jie-Hui Gong Dept. of Comp. Sci. and Technol of curved surfaces [Liu et al. 2001; Gong et al. 2006b]. The CSG oriented approach, however, is generally